Subjects -> TRANSPORTATION (Total: 214 journals)
    - AIR TRANSPORT (9 journals)
    - AUTOMOBILES (26 journals)
    - RAILROADS (10 journals)
    - ROADS AND TRAFFIC (9 journals)
    - SHIPS AND SHIPPING (43 journals)
    - TRANSPORTATION (117 journals)

TRANSPORTATION (117 journals)                     

Showing 1 - 53 of 53 Journals sorted by number of followers
Journal of Navigation     Hybrid Journal   (Followers: 203)
Accident Analysis & Prevention     Hybrid Journal   (Followers: 111)
Transportation Research Part B: Methodological     Hybrid Journal   (Followers: 38)
Transportation Research Part A: Policy and Practice     Hybrid Journal   (Followers: 38)
Urban, Planning and Transport Research     Open Access   (Followers: 33)
Transportation     Hybrid Journal   (Followers: 32)
Transportation Research Record : Journal of the Transportation Research Board     Full-text available via subscription   (Followers: 29)
Transportation Research Part C: Emerging Technologies     Hybrid Journal   (Followers: 29)
Journal of Transport and Land Use     Open Access   (Followers: 28)
Transportation Science     Full-text available via subscription   (Followers: 26)
Journal of Transport Geography     Hybrid Journal   (Followers: 22)
European Transport Research Review     Open Access   (Followers: 22)
Public Transport     Hybrid Journal   (Followers: 18)
Nonlinear Dynamics     Hybrid Journal   (Followers: 18)
International Journal of Sustainable Transportation     Hybrid Journal   (Followers: 18)
Cities in the 21st Century     Open Access   (Followers: 17)
Economics of Transportation     Partially Free   (Followers: 16)
Open Journal of Safety Science and Technology     Open Access   (Followers: 16)
Transportation Journal     Full-text available via subscription   (Followers: 16)
Transport     Open Access   (Followers: 16)
Journal of Transportation Technologies     Open Access   (Followers: 13)
IET Electrical Systems in Transportation     Open Access   (Followers: 13)
Case Studies on Transport Policy     Hybrid Journal   (Followers: 13)
International Journal of Intelligent Transportation Systems Research     Hybrid Journal   (Followers: 13)
Journal of Supply Chain Management Science (JSCMS)     Open Access   (Followers: 13)
Journal of Advanced Transportation     Hybrid Journal   (Followers: 12)
International Journal of Traffic and Transportation Engineering     Open Access   (Followers: 12)
Journal of Transport & Health     Hybrid Journal   (Followers: 12)
European Journal of Transport and Infrastructure Research (EJTIR)     Open Access   (Followers: 12)
Journal of Transport History     Hybrid Journal   (Followers: 12)
EURO Journal of Transportation and Logistics     Open Access   (Followers: 12)
Sport, Education and Society     Hybrid Journal   (Followers: 12)
Transport Reviews: A Transnational Transdisciplinary Journal     Hybrid Journal   (Followers: 11)
IET Intelligent Transport Systems     Open Access   (Followers: 11)
Modern Transportation     Open Access   (Followers: 11)
International Journal of Physical Distribution & Logistics Management     Hybrid Journal   (Followers: 11)
Proceedings of the Institution of Mechanical Engineers Part F: Journal of Rail and Rapid Transit     Hybrid Journal   (Followers: 11)
International Journal of Crashworthiness     Hybrid Journal   (Followers: 10)
Journal of Sport & Social Issues     Hybrid Journal   (Followers: 10)
Journal of Transport and Supply Chain Management     Open Access   (Followers: 9)
Travel Behaviour and Society     Full-text available via subscription   (Followers: 9)
Journal of Transportation Safety & Security     Hybrid Journal   (Followers: 9)
International Journal of Transportation Science and Technology     Open Access   (Followers: 9)
Pervasive and Mobile Computing     Hybrid Journal   (Followers: 8)
Analytic Methods in Accident Research     Hybrid Journal   (Followers: 8)
International Journal of Mobile Communications     Hybrid Journal   (Followers: 8)
Transportation Infrastructure Geotechnology     Hybrid Journal   (Followers: 8)
Transportmetrica A : Transport Science     Hybrid Journal   (Followers: 7)
Journal of Modern Transportation     Full-text available via subscription   (Followers: 7)
Journal of Waterway Port Coastal and Ocean Engineering     Full-text available via subscription   (Followers: 7)
International Journal of Electric and Hybrid Vehicles     Hybrid Journal   (Followers: 7)
IEEE Vehicular Technology Magazine     Full-text available via subscription   (Followers: 7)
Mobility in History     Full-text available via subscription   (Followers: 7)
Transportation Research Procedia     Open Access   (Followers: 6)
International Journal of Heavy Vehicle Systems     Hybrid Journal   (Followers: 6)
Journal of Mechatronics, Electrical Power, and Vehicular Technology     Open Access   (Followers: 6)
Applied Mobilities     Hybrid Journal   (Followers: 5)
World Review of Intermodal Transportation Research     Hybrid Journal   (Followers: 5)
International Journal of Applied Logistics     Full-text available via subscription   (Followers: 5)
Logistics & Sustainable Transport     Open Access   (Followers: 4)
Journal of Traffic and Transportation Engineering (English Edition)     Open Access   (Followers: 4)
Transportation Letters : The International Journal of Transportation Research     Hybrid Journal   (Followers: 4)
Transport and Telecommunication     Open Access   (Followers: 4)
Vehicular Communications     Full-text available via subscription   (Followers: 4)
IEEE Open Journal of Intelligent Transportation Systems     Open Access   (Followers: 4)
Research in Transportation Business and Management     Partially Free   (Followers: 4)
Transport Problems     Open Access   (Followers: 4)
Transactions on Transport Sciences     Open Access   (Followers: 4)
World Electric Vehicle Journal     Open Access   (Followers: 3)
Journal of Transportation and Logistics     Open Access   (Followers: 3)
Journal of Public Transportation     Open Access   (Followers: 3)
TRANSPORTES     Open Access   (Followers: 3)
Journal of Transportation Security     Hybrid Journal   (Followers: 3)
International Journal of Vehicle Systems Modelling and Testing     Hybrid Journal   (Followers: 2)
Packaging, Transport, Storage & Security of Radioactive Material     Hybrid Journal   (Followers: 2)
Sport, Ethics and Philosophy     Hybrid Journal   (Followers: 2)
Streetnotes     Open Access   (Followers: 2)
Journal of Big Data Analytics in Transportation     Hybrid Journal   (Followers: 2)
Travel Medicine and Infectious Disease     Hybrid Journal   (Followers: 2)
International Journal of Transportation Engineering     Open Access   (Followers: 2)
Transportation Research Interdisciplinary Perspectives     Open Access   (Followers: 2)
Journal of Intelligent and Connected Vehicles     Open Access   (Followers: 1)
Open Transportation Journal     Open Access   (Followers: 1)
eTransportation     Open Access   (Followers: 1)
Transportmetrica B : Transport Dynamics     Hybrid Journal   (Followers: 1)
Transportation Safety and Environment     Open Access   (Followers: 1)
Danish Journal of Transportation Research / Dansk Tidsskrift for Transportforskning     Open Access   (Followers: 1)
Asian Transport Studies     Open Access   (Followers: 1)
Transportation Engineering     Open Access   (Followers: 1)
International Journal of Ocean Systems Management     Hybrid Journal   (Followers: 1)
Decision Making : Applications in Management and Engineering     Open Access   (Followers: 1)
Transportation Geotechnics     Full-text available via subscription   (Followers: 1)
Romanian Journal of Transport Infrastructure     Open Access   (Followers: 1)
International Journal of Services Technology and Management     Hybrid Journal   (Followers: 1)
Les Dossiers du Grihl     Open Access   (Followers: 1)
Logistics     Open Access   (Followers: 1)
Synthesis Lectures on Mobile and Pervasive Computing     Full-text available via subscription   (Followers: 1)
Botswana Journal of Technology     Full-text available via subscription   (Followers: 1)
Emission Control Science and Technology     Hybrid Journal   (Followers: 1)
Recherche Transports Sécurité     Hybrid Journal   (Followers: 1)
Maritime Transport Research     Open Access  
Communications in Transportation Research     Open Access  
IET Smart Cities     Open Access  
Journal on Vehicle Routing Algorithms     Hybrid Journal  
Transportation in Developing Economies     Hybrid Journal  
Vehicles     Open Access  
Periodica Polytechnica Transportation Engineering     Open Access  
Transportation Systems and Technology     Open Access  
LOGI ? Scientific Journal on Transport and Logistics     Open Access  
Promet : Traffic &Transportation     Open Access  
IFAC-PapersOnLine     Open Access  
Revista Transporte y Territorio     Open Access  
Транспортні системи та технології перевезень     Open Access  
Geosystem Engineering     Hybrid Journal  
Logistique & Management     Hybrid Journal  
IATSS Research     Open Access  
Transport in Porous Media     Hybrid Journal  

           

Similar Journals
Journal Cover
Proceedings of the Institution of Mechanical Engineers Part F: Journal of Rail and Rapid Transit
Journal Prestige (SJR): 0.494
Citation Impact (citeScore): 1
Number of Followers: 11  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0954-4097 - ISSN (Online) 2041-3017
Published by Sage Publications Homepage  [1174 journals]
  • Sources of variability in metro train-induced vibration

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      Authors: Xiangyu Qu, David Thompson, Meng Ma, Minghang Li, Evangelos Ntotsios
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      In previous in-situ measurements of metro trains it has been found that the velocity level on the track or tunnel wall may vary significantly between different train passages, even though the measuring section, the type of trains and the track and tunnel conditions are identical. An investigation is carried out into the sources of this variability, using a 3D train-track numerical model. This is built using the software SIMPACK and ABAQUS, and is connected through one-way coupling to a finite element model of the tunnel and soil. These models are used to study the influence of various train parameters, including the wheel and rail unevenness, train speed and degree of train loading. For comparison, in-situ measurements were made of the dynamic response of the rail and tunnel wall. The rail roughness at the site as well as the wheel unevenness of all 48 wheels for one train were measured. The results from the model indicate that the wheel unevenness affects the rail velocity level in the frequency region between 25 and 250 Hz and tunnel wall vibration above 5 Hz. The rail velocity level can vary by up to 20 dB due to wheel unevenness, with the largest variations occurring in the frequency bands 50–63 Hz. Variations in passenger loading affect the train-induced vibration by up to 4.5 dB, mainly in the low frequency region. When the train speed varies within a range of ±20% relative to the nominal speed 60 km/h, the frequencies of the peaks are shifted and the level in some frequency bands can change by as much as 10 dB. However, the largest influence is that of the wheel unevenness. It is concluded that the variation in these parameters, especially the wheel and rail unevenness, should be considered to achieve reliable predictions of train-induced vibration.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-08-11T06:18:00Z
      DOI: 10.1177/09544097221118456
       
  • Rail gage-based risk detection Using iPhone 12 pro

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      Authors: Yihao Ren, Zhenyu Dai, Pan Lu, Chengbo Ai, Ying Huang, Denver Tolliver
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      Federal Railroad Administration strictly regulates the inspection frequency of all track classes to ensure timely identification of rail defects including irregular gage which is a devastating rail geometry defect. Conventional rail inspection methods are both costly and labor-intensive, whereas existing novel technologies can be expensive and mostly focus on a specific inspection area, e.g. vertical alignment. iPhone 12 Pro was introduced to the public recently with a low-cost, low-resolution light detection and ranging (LiDAR) sensor that is purposed for better photography and virtual reality. Thanks to its portability and computational capacity, iPhone 12 Pro can potentially be used as a portable solution for irregular gage inspection, whose capacity and feasibility are unknown. This study first investigated the capability of the iPhone 12 Pro in calculating unloaded rail gages by its embedded LiDAR sensor. The results showed that uncalibrated raw gage values measured by the iPhone 12 Pro LiDAR sensor were systematically lower than the ground-truth values. The proposed method in this study then introduced logistic regression to calibrate the measured values through balancing the prediction performance and the efficiency, followed by validations using a Gaussian process classifier. The results show that the proposed method correctly identified all 39 high-risk locations with 227 false alarmed locations. The proposed method with the iPhone 12 Pro LiDAR sensor could potentially narrow down the possible “high-risk” gage sections and may result in a significant reduction in the field inspection workload by 48%.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-08-05T10:26:24Z
      DOI: 10.1177/09544097221116431
       
  • Gauge widening failures of wagon wheels in Indian Railways: Finite element
           modeling and observed statistics

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      Authors: Sundareswaran S, MRK Vakkalagadda, V Racherla, Senthil Kumar A, KP Vineesh
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      There were many gauge widening cases identified in wagon wheels of Indian Railways during the past decade, but no investigation was conducted to analyse the failures. The present work aims to investigate the main cause of failures in wagon wheels due to gauge widening. A train running model is used to estimate heat generation at wheel and brake block interface. A finite element model is used to estimate temperature and stress state in the wheel during heat treatment, wheel and axle fitment, and braking. Heat partition between brake blocks and wheel is considered for the analysis. Further, heat losses to the environment because of convection and radiation are also incorporated in the model. The wheel gauge reduces during the braking process and the permanent wheel gauge increases during the cooling process. Permanent wheel gauge increases with non-uniformity in braking and a higher frequency of braking.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-08-04T12:43:39Z
      DOI: 10.1177/09544097221116255
       
  • Discrete modeling and calculation of traction return-current network for
           400 km/h high-speed railway

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      Authors: Shiwu Yang, Chang Liu
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      The planned 400 km/h high-speed train capable of cross-border intermodal transportation will inevitably cause a greater return-current and bring more challenges to signaling infrastructure and integrated grounding while achieving stronger traction. Based on the existing AC autotransformer power supply mode, this paper proposes a discrete modeling and calculation method of the traction return-current network concerning impedance equivalent, realizing the simulation and quantitative analysis of the return-current distribution of multiple current-carrying conductors in the block section and station yard under the double-track condition. Then, the dynamic distribution is analyzed comprehensively considering traction power supply, signaling, and integrated grounding systems. Also, the method is verified with field test data. Finally, the simulation of the return-current proportion of multiple conductors is carried out under the dynamic operating conditions of high speed, and the distribution characteristics are compared and analyzed under different ballast resistances. In the most unfavorable case, the maximum return-current in the rails, grounding wire, and protective wire can reach 1046 A, 180 A, and 126 A, respectively. This work helps evaluate the electromagnetic compatibility between signaling and strong currents in engineering practice, further optimize the capacity configuration of equipment along the railway lines, and improve the signaling immunity design.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-08-04T12:11:59Z
      DOI: 10.1177/09544097221116966
       
  • A year-round analysis of railway station overruns due to low adhesion
           conditions

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      Authors: Ben White, Mike Watson, Roger Lewis
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      Key Performance Indicators, such as station overruns and delay minutes, are used to assess the performance and punctuality of the GB railway. They can be used to quantify the effects of low adhesion, but the majority of previous analysis has been constrained to the autumn season. A Python script has been created in this work to extract 11 years of detailed passenger and freight station overrun data, throughout the entire year. The information gathered includes time and date, location, direction, vehicle type, railhead conditions and subsequent delay minutes caused by the incident. Although the majority of low adhesion related overruns occur in the autumn season due to leaf fall, this work has highlighted the number of low adhesion related issues that occur throughout the year where there are no visible signs of contamination. This work gives an overview of this new dataset and looks at some key trends in the data but the granular detail available means that future case studies could be carried out in specific locations, linked to geographic and meteorological data, to assess when and why low adhesion is occurring. From an operational perspective, the dataset could then be used as a daily updated assessment of the effectiveness of low adhesion mitigation methods.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-08-04T05:00:28Z
      DOI: 10.1177/09544097221117314
       
  • Effect of material failure criteria on collision behavior of metro vehicle
           end structures

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      Authors: Xiaorui Wang, Tao Zhu, Jingke Zhang, Haoxu Ding, Shoune Xiao, Liantao Lu, Bing Yang, Guangwu Yang, Yuxin Liu
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      This study comprehensively analyzes the failure behavior of metro vehicle end structures (VESs) during collisions, using the common material SUS301L-MT in a stainless steel metro and its VES as the research object. First, constitutive and failure tests are performed on the material, the macro–micro characterization of its mechanical properties is performed, and the failure strains and morphologies under various stress states are obtained and discussed. Subsequently, two failure criteria, Von Mises (VM) and Generalized Incremental Stress State Dependent Damage Model (GISSMO), are calibrated and established. Finally, the crashworthiness evaluation indexes of the VES are defined, and vertical offset collisions of metro VESs for different speed levels are numerically analyzed. The results show that the stress triaxiality significantly affects the failure strain of stainless steel SUS301L-MT, with the maximal difference for different stress states reaching 51.10%. SUS301L-MT stainless steel exhibits strain-rate strengthening and yield hysteresis effects. Overall, the numerical results for the VM criterion are worse than for the GISSMO criterion, which more accurately describes the collision behavior of metro VESs under complex stress states.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-08-03T06:02:49Z
      DOI: 10.1177/09544097221116520
       
  • A new small sample test configuration for fatigue life estimation of
           overhead contact wires

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      Authors: Özgün Sunar, David Fletcher
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      Fatigue in railway overhead line electrification (OLE) contact wires can cause sudden catastrophic failures. The contact wire interacting with the pantograph both mechanically and electrically is subjected to tension and repetitive bending due to the pantograph contact force. Recently, fatigue failures of OLE have risen in prominence with increases in train speed. To address this a new fatigue test configuration has been developed. The study focuses on a method for testing the wire as a component enabling fatigue life evaluation of worn wires, or exploring the effect of installation damage, through component level evaluation of crack initiation and propagation. The new test configuration places a 400 mm-length contact wire in a combination of bending and pretension with realistic boundary conditions replicating service conditions for longer spans. The results are presented in a strain-life format to provide data for a wide range of potential service conditions.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-08-03T03:07:30Z
      DOI: 10.1177/09544097221116531
       
  • Wind tunnel testing on the aerodynamic effect on a train with single-sided
           and double-sided wind barriers of different lengths

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      Authors: Houyu Gu, Tanghong Liu, Hongrui Gao, Zhiqi Liu, Sijin Cheng
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      In this study, wind tunnel tests were used to study the effect of changes in the length of a wind barrier on the aerodynamic performance of a train with single-sided and double-sided wind barriers. The results showed that in the condition of a double-sided wind barrier, as the length of the wind barrier increased, the pressure change on the windward side of the train was significantly smaller than that of the single-sided wind barrier. When the length of the wind barrier is less than 21.67 H (H is the height of the train), in the condition of the two types of wind barrier, the direction of the side force coefficient is opposite to the direction of the incoming flow. As the length of the wind barrier changes, the drag coefficient with the double-sided wind barrier is obviously more stable than that with the single-sided wind barrier. For the drag coefficient and lift coefficient, under the condition of double-sided wind barrier, when the length of the wind barrier is greater than 23.65 H, the change amplitude is lower than that of the single-sided wind barrier. For the running safety of the train, it is conservative and approximately accurate at the single-sided barrier length of 25.63 H and double-sided barrier length of 23.65 H.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-07-19T01:55:45Z
      DOI: 10.1177/09544097221116551
       
  • Influence of the coupler and buffer device on the train collision safety

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      Authors: Hechao Zhou, Yuwei Wang, Xupeng Wang, Jun Zhan, Jimin Zhang
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      Based on the multi-body dynamics the three-dimensional train collision model including a more detailed coupler-buffer substructure is established in this paper. During the train collision, the dynamic responses of the coupler-buffer substructure are comprehensively analysed. Some key parameters, such as the coupler initial deflection angle, max-angle, plunger spring stiffness and buffer impedance force, are investigated and their effects on the train derailment are also evaluated. According to the simulation results it is indicated that at present the coupler-buffer device is designed mainly from the point of view of the normal operation condition. Compared with the normal operation, in the train collision condition the longitudinal impact force is so large that the coupler-buffer device reveals a very weak ability to anti-jackknifing. As a result, in most cases the coupler rotation angle is very large and equal to its designed max-angle. Under the effect of this large coupler rotation angle, the collided trains have a high risk to derail. The importance of the anti-jackknifing of the coupler and buffer device is illustrated in this paper, which has a great influence on the train collision safety and should not be neglected. In order to improve the safety against derailment, it is suggested to decrease the coupler’s max-angle and increase its plunger spring stiffness. Alternatively, a friction arc coupler yoke connection design is suggested to replace the current coupler yoke design.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-07-14T07:28:39Z
      DOI: 10.1177/09544097221115037
       
  • Assessing the fast non-Hertzian methods for wheel-rail rolling contact
           integrated in the vehicle dynamics simulation

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      Authors: Yu Chen, Yaoliang Sun, Wenhao Ding, Ping Wang
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      An accurate and high-efficiency contact model is essential for vehicle-track dynamic simulation and wear prediction. The paper attempts to assess the influence of different contact models on the offline and online simulation, as well as wear depth distribution. Taking CONTACT as the reference model, the computational accuracies of contact model combinations (i.e. Hertz + FASTSIM, Kik–Piotrowski (KP) + FASTSIM, modified Kik–Piotrowski (MKP) + FASTSIM and MKP + FaStrip) are evaluated. Typical wheel-rail contact cases and two dynamic simulation cases (track irregularity and curve track) have been studied. Results show that MKP + FaStrip achieves the best computational accuracy in calculating the typical wheel-rail contact situation, besides, the yaw angle has a significant influence on the contact patch shape and pressure distribution, especially when the wheel flange contacts with a rail corner. With regard to the vehicle passing the track with the lateral irregularity, both KP + FASTSIM and MKP + FaStrip models can achieve relatively good agreement on dynamic results and wear prediction with CONTACT. In terms of the curve track, MKP + FaStrip has better accuracy on dynamic results and wear due to a larger yaw angle.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-07-14T02:41:04Z
      DOI: 10.1177/09544097221113462
       
  • Design and optimization of nine degrees of freedom suspension model for
           hyperloop pods

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      Authors: Pratik Madhan, Shantanu Gaikwad, Brajesh Panigrahi
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      The concept of Hyperloop systems is proposed to cater the needs of high-speed transportation of goods and passengers. This technology comprises low-pressure tubes, pods and terminals. The pods travel inside the low-pressure tubes at very high speed between the terminals. One of the crucial aspects of this technology is the design of suspension systems for pod stability. It has been accentuated that a wheel-based suspension system is a superior option for subsonic speed travel with the minimum achievable technology and leaving higher performance for future developments. Therefore, a nine DOF wheel-based suspension model is proposed for Hyperloop pods in the present work. The design of the proposed suspension model is developed considering the high acceleration and normal and emergency braking events in Hyperloop systems. The objective of the proposed design is to minimize pod displacements due to various possible excitations. Equation of motion for the model is firstly derived, and the responses for the various excitations are obtained using a Simulink model and Newmark β method. Subsequently, the design parameters of the proposed model are optimized using the Simulink optimization tool. The response of the pod with the proposed suspension model is compared with the responses of existing suspension models to ensure better pod stability. Finally, acceleration and braking events in the Hyperloop environment are considered with the load transfer mechanism. Subsequently, a parametric study on the response of the Hyperloop pods with a proposed suspension model with optimized parameters is performed considering normal and emergency braking events.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-07-13T06:50:13Z
      DOI: 10.1177/09544097221112580
       
  • Quantification of longitudinal fastener stiffness and the effect on
           fastening system loading demand

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      Authors: Christian Khachaturian, Marcus S Dersch, J Riley Edwards, Matheus Trizotto
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      Over the past 20 years, there have been at least 10 derailments due to spike fastener fatigue failures in North America. These fatigue failures have been considered a moderate to severe challenge that require manual walking inspections that are both time and labor intensive. These fatigue failures have been found to result from spike overloading due to lateral and longitudinal loads. To date, there has been limited quantification of the vertical, lateral, and longitudinal fastener forces in track. This paper quantifies the effect of fastener type on fastener load to account for various track types and locations. Laboratory experimentation was performed to quantify the stiffness of multiple fastening systems and this data was input into a previously validated analytical model to quantify the effect of stiffness on fastener loading. Additional laboratory experimentation was performed to quantify the relationships between both fastening system type and vertical loading and spike strain. While the laboratory data indicate a significant variance in stiffness between fastening systems, the model results indicate that the load transferred to the fastening system is less sensitive. However, spike strain data indicate the load path was affected by fastener type and vertical load. The characterization of longitudinal stiffness of multiple fastening systems and the relationship to spike load as presented can be used to advance track mechanistic-empirical design and improve rail neutral temperature prediction and track buckling models.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-07-04T11:45:29Z
      DOI: 10.1177/09544097221112576
       
  • Comparative analysis of the aerodynamic performance of trains and dynamic
           responses of catenaries for windbreak walls with different heights under
           crosswind

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      Authors: Xiao Dong, Tanghong Liu, Yutao Xia, Fan Yang, Zhengwei Chen, Zijian Guo
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      Due to the deterioration of the crosswind-protection performance of the original earth embankment windbreak walls on the train with increased speed, researching the influence of the heightened windbreak walls on aerodynamic performances of trains as well as the protection of the catenary is necessary for optimizing the windproof performance. The improved delayed detached eddy simulation based on the shear stress transport (SST) κ-ω turbulence model was employed to simulate flow structures. Furthermore, the effect on the displacement of the catenary was investigated using the finite element method (FEM). The numerical case was validated against the field tests. The results show that the aerodynamic performances of the train were improved as the windbreak wall was heightened by 0.5 m. Whereas, further heightening the windbreak wall worsened the aerodynamic performance. When the windbreak wall was heightened by 0.5 and 1 m, the wind speed of the catenary was reduced by 31.17% and 53.87%, and the displacement of the catenary was reduced by 48.09% and 74.11%, respectively, compared with that of the original windbreak wall. These results reveal that the wind-protection performance on the train and catenary can be both improved by reasonably heightening windbreak walls.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-07-01T04:37:15Z
      DOI: 10.1177/09544097221112506
       
  • A Petri net asset management framework for railway switches and crossings

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      Authors: Jack Litherland, John Andrews
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      Switches and Crossings (S&C) are a fundamental part of any railway network, they allow trains to switch between tracks and to cross over other tracks. They consist of various electrical and mechanical components to which there is a substantial maintenance cost. Failure of an S&C unit can cause significant disruption to traffic and have large financial implications. Therefore, planning their maintenance is of critical importance to railway asset managers. This research proposes an asset management framework, which models the degradation, failure, inspection and maintenance for the S&C unit. The framework comprises nine Petri net sub-models for the S&C component availability and predicts the number of maintenance interventions in a given time period. This can be used to inform maintenance decision making, with the aim of reducing the life cycle cost of the S&C.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-06-28T02:22:02Z
      DOI: 10.1177/09544097221110970
       
  • Image-based 3D reconstruction for rail profile measurement

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      Authors: Dongyu Zhang, Siva N Lingamanaik, Hoam Chung
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      The routine inspection of railheads for defects such as wear and surface cracks is a tedious process, which, if not detected, can alter the wheel-rail contact interaction leading to catastrophic events. This study investigates and implements a railhead measurement method using image-based three-dimensional reconstruction, which enables rapid scanning of railheads and production of detail cross-sectional measurements for rail-wheel interface analysis. A complete workflow with a methodology for reconstructing railheads from images and extracting cross-sectional measurements from the reconstructed model is presented. In order to validate the proposed method in the field, a mobile automated system was equipped with an array of cameras specifically spaced to cover the areas of interest on the railhead. The system can automatically transverse along the railhead, acquiring images synchronously. Two case studies in the laboratory environment and the real railway site have been performed to evaluate the performance and accuracy against industry practices. The results show that the proposed method can accurately measure the railhead cross-sectional profile at an root mean square error (RMSE) less than 0.3 mm compared with MiniProf. Furthermore, continuous cross-sectional data and intuitive color information are provided by our method which can help inspectors to locate defects easily and more efficiently.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-06-24T01:03:50Z
      DOI: 10.1177/09544097221110322
       
  • Horizontal curvature estimation of tram tracks using OpenStreetMap

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      Authors: Tobias Bettinger, Philipp Leibner, Christian Schindler
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      For analysing, understanding and predicting the track/train-dynamics in order to develop comfortable and sustainable vehicles a sufficient description of the track course and conditions are key requirements. Not only the track irregularities but also the horizontal curvature affects the vehicle dynamics strongly. Nearly all cities owning light rail systems have gradually established the light rail traffic. By reasons of building density, road transportation infrastructure, and progress of the overall urban planning, the light rail infrastructure was constrained to the pre-existing environment. Thus, the track course is mainly optimized for efficient space use but not for best possible vehicle dynamics. To be able to analyse the track layout of tram networks at a bigger scale, an appropriate methodology that allows acquiring track course data is needed, which is the main objective of this paper. For this purpose, an open data approach was developed by the authors utilizing OpenStreetMap (OSM) to derive the horizontal track curvature based on geodata. This groundbreaking approach improves the state of the art since professional geodetic measurements of light rail tracks are generally rarely publicly available, cost-intensive and their preprocessing can potentially be time consuming. The outcome is a simple, robust, and fast approach that was validated using already existing reference track data which was available to the authors. Additionally, an error estimation of the methodology was carried out. Using a quadratic error function, the median standard deviation of the curvature can be determined and used to rate the exactness of the estimated curvature depending on its magnitude. In this approach, the curvature estimations exactness is generally high for small curve radii and decreases for bigger radii. Therefore it can be concluded that the field of application is especially promising for light rail infrastructure. But also for mainline tracks the new method can be used as a rough estimate, if no curvature data is at hand.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-06-17T09:19:08Z
      DOI: 10.1177/09544097221106851
       
  • Dynamic diagnosis method and quantitative characterization of rail
           corrugation

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      Authors: Xiaodi Xu, Jinzhao Liu, Shanchao Sun, Liubin Niu, Xuegeng Mao
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      This paper describes a dynamic and quantitative method of diagnosing and estimating rail corrugation in railway tracks using acceleration data obtained from high-speed comprehensive inspection train. Although the amplitude of rail corrugation is small, it will arouse violent vibration between the wheel and rail under high-speed conditions, and accelerate the structural damage of track-vehicle system components. Combined with high-frequency Axle Box Acceleration (ABA), a time-frequency analysis-based Rail Corrugation Index and Energy Factor method are proposed to diagnose the rail corrugation of high-speed railway. The corrugation amplitude is estimated by the quadratic integral of filtered ABA. The new evaluation method uses the windowed energy index signal of the ABA to replace the original signal, and demodulates the high-frequency discrete response signal into a stable low-frequency energy signal without losing the vibration characteristics. Inverse SSTFT is applied to estimate the amplitude of rail corrugation. High-speed railway application results show that the proposed index can effectively diagnose the rail corrugation dynamically and quantitatively and estimate the degree of it.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-06-13T07:57:05Z
      DOI: 10.1177/09544097221107985
       
  • Nonlinear effects of a new mesh-type rail pad on the coupled vehicle-slab
           track dynamics system under extremely cold environment

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      Authors: Zhihao Zhai, Shengyang Zhu, Xuancheng Yuan, Zhenxing He, Chengbiao Cai
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      Nonlinear dynamic behavior of a new mesh-type rail pad on the vehicle-slab track coupled system is investigated considering the influences of frequency and amplitude dependence in extremely cold environment. The frequency dependence of the new mesh-type rail pad is modeled by a fractional derivative viscoelastic element while a frictional component considers the amplitude dependence. Laboratory tests are performed to investigate the frequency and amplitude dependent performance of the rail pad and to determine key model parameters. Temperature factor and Mooney-Rivlin strain energy density are also introduced to simulate the mechanical properties of the rubber material of rail pad in low temperature environments. Further, the proposed nonlinear model for the rail pad is implemented in a coupled vehicle-slab track dynamics model to investigate the complicated nonlinear effects of the rail pad due to the dependence of the temperature, amplitude and frequency. The analysis indicates that the dynamic stiffness and damping of the mesh-type rail pads increase with the frequency increases. The proposed model for the mesh-type rail pad enables a more accurate dynamic simulation of vehicle-slab track system in extremely cold environment than the traditional Kelvin-Voigt model which overestimates the wheel rail force, rail vibration acceleration and other indicators at 3.15 Hz–40 Hz and 250 Hz–500 Hz, while underestimates these indicators at 50 Hz–125 Hz.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-06-13T07:37:32Z
      DOI: 10.1177/09544097221107472
       
  • A Method for Maintaining Virtually Coupled States of Train Convoys

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      Authors: Yu Liu, Dongxiu Ou, Yuanxiang Yang, Decun Dong
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      Virtual coupling, which provides great advantages in operational flexibility and line capacity, is an advanced signaling concept for the railway industry. The dynamic disturbances caused by line conditions might change the coupled movements of the train convoy into abnormal states, which means the speed difference and separation distance of the adjacent trains exceed the given thresholds. This paper proposes a method to maintain the coupled states using terminal sliding mode control (SMC) based on second-order nonlinear train dynamics, with a nonlinear observer eliminating the estimation error due to time-varying measurement delay. The controller calculates the optimal unit effective tractive force for the following train in real-time, taking the leader velocity and desired separation as control targets. The simulation of a two-train convoy on a high-speed railway is conducted including different abnormal scenarios. The results demonstrate that the proposed method eliminates the observation errors and achieves synchronous convergence of the tracking errors while guaranteeing passenger comfort, and that it outperforms traditional SMC.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-06-12T08:38:43Z
      DOI: 10.1177/09544097221103333
       
  • Optimisation of wheelset maintenance by using a reduced flange wear wheel
           profile

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      Authors: Yousif Muhamedsalih, Gareth Tucker, Julian Stow
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      This paper investigates whether it is possible to develop a wheel profile design that will extend wheelset life compared to an existing commonly used Great Britain passenger wheel profile, the P8. The P8 wheel profile was originally developed in the late 1960s as an alternative to a 1:20 coned wheel profile (the P1). The P1 often required frequent turning as the conicity could increase quickly over time as the wheel wore in service. The P8 was designed based on an average worn shape of a P1 wheel. The P8 was found to stay closer to its original shape as it wore in service. However, new P8 wheels or newly profiled P8 wheels tend to experience a high initial flange wear rate in the first 20,000–30,000 miles, until the worn wheel shape reaches ‘dimensional stability’; after this, the flange width typically remains relatively constant. A ‘Reduced Flange Wear’ (RFW) wheel profile has been developed, based on the P8 profile but with a modified flange root geometry. The Wheel Profile Damage Model has been used to calculate how the proposed RFW wheel profile could reduce wear rates and therefore increase wheelset life. This paper presents results for a typical electric multiple unit train (EMU1) running on rural and suburban routes and a higher speed variant (EMU2) running on an inter-city route. The effect of the proposed RFW profile on rail rolling contact fatigue (RCF) has also been evaluated using the Whole Life Rail Model, for the same routes. The results suggest that the proposed RFW profile does reduce flange wear compared to a P8, with larger reductions achieved on routes that are more curvaceous. For wheel turning based purely on restoring wheel profile geometry, the RFW profile could half the amount of material removed at each turning (based on turning wheels at 250,000 miles). Furthermore, the results show that the RFW profile experiences slightly less wheel RCF damage than the P8. When new, the RFW profile appears to cause slightly higher rail RCF than a new P8 (For radii 700 m < R < 1300 m); however, the results suggest that worn RFW profiles cause very similar rail RCF to that caused by worn P8 wheels.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-06-01T07:14:34Z
      DOI: 10.1177/09544097221105959
       
  • A reliability study of railway switch and crossing components

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      Authors: Jack Litherland, John Andrews
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      Within any railway network Switches and Crossings (S&C) are essential. They allow trains to change tracks, allowing different routes to be selected. Despite their necessity, they generally have a lower reliability than plain line track and are often subject to breakdowns due to the high number of interlinking electrical and mechanical components they contain. Due to their location such as station throats and major junctions, S&C breakdown is generally very disruptive to traffic causing significant delays. Ensuring that S&C units are maintained correctly and minimising their risk of failure, is therefore of critical importance to railway asset managers. This research uses maintenance and failure data to determine probability distributions for the degradation, failure, inspection and maintenance of nine critical components within S&C units. These distributions can then be used within an asset management framework to simulate the expected operational behaviour of an S&C unit under a given set of conditions, allowing more informed asset management decisions to be taken.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-05-21T01:32:05Z
      DOI: 10.1177/09544097221100672
       
  • New methods for dynamically substructured system testing of a railway car
           pantograph

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      Authors: Shigeyuki Kobayashi, Tatsuya Koyama, Satoshi Harada, David P Stoten
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      This study proposes new pantograph testing methods for railway pantograph/overhead catenary systems (OCS), based upon substructured testing consisting of a physical pantograph and a numerical OCS model. Hence, this work builds upon a previously presented work, (using the dynamically substructured system approach developed by Stoten and Hyde), which was conducted on a relatively simple mechanical structure in the Automatic Control and Test Laboratory (ACTLab), University of Bristol, UK.In this current paper, the dynamically substructured system (DSS) testing method is applied to a real shinkansen pantograph, using various actuator/DSS configurations that have been implemented at the Railway Technical Research Institute, Tokyo, Japan. In the first of these tests, a conventional servohydraulic actuated rig is used to represent phenomena due to the dropper-passing frequency. Resulting DSS test data are compared with those generated by a numerical simulation of the emulated system, i.e. the system to be represented by the DSS experimentation.Then, in the second set of investigations, the DSS method is used in conjunction with a new ‘rotational disc’ test rig that is arranged to be in dynamic interaction with the shinkansen pantograph contact head. This novel experimental system enables the investigation of dynamic interactions between the overhead catenary system contact wire and the pantograph head, due to span-passing. Again, results from this experimental investigation are compared with those generated by a purely numerical simulation of the emulated system.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-05-20T06:21:55Z
      DOI: 10.1177/09544097221094661
       
  • Analytical and experimental investigation of composite pads created by
           using coke dust against the fading problem in railway vehicles

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      Authors: A Unal, N Akkus
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      In this study, the effects of using coke dust in brake pad mixtures against the problem of friction coefficient reduction occurring at high temperatures in railway vehicle brake pads were investigated. For this purpose, the average friction coefficients and wear rates of the brake pads produced by using different amounts of coke dust were tested with the help of a dynamometer at different temperature values and the brake pad mixture containing coke dust with optimum ratio was determined. Brake pads with optimum coke dust ratio were tested in a train set under real railway conditions and the stopping distances of the train set and the temperatures during braking were measured. Using the stopping distances measured during railway tests and the average friction coefficients of the brake pads were analyzed analytically and compared with the dynamometer results. As a result of these tests, it has been observed that the coke dust material reduces the friction coefficient at low temperatures, but increases the friction coefficient at high temperatures and significantly reduces the amount of wear.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-05-20T04:27:16Z
      DOI: 10.1177/09544097221100920
       
  • Micro-pressure wave radiation from tunnel portals in deep cuttings

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      Authors: Honglin Wang, Alan E Vardy, Haiquan Bi
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      The reflection and radiation of steep-fronted wavefronts at a tunnel exit to a deep cutting is studied and contrasted with the more usual case of radiation from over-ground portals. A well-known difference between radiation in odd and even dimensions is shown to have a significant influence on reflected wavefronts, notably causing increased distortion that complicates analyses, but that can have practical advantages when rapid changes are undesirable. Likewise, micro-pressure waves radiating from the portal into a cutting are shown to exhibit strong dispersion that does not occur in the corresponding radiation into an open terrain. In the latter case, formulae that represent the behaviour of monopoles and dipoles are commonly used to estimate conditions beyond tunnel portals, but no such simple formula exists (or is even possible) for cylindrical radiation that is characteristic of MPWs in cuttings. An important outcome of the paper is the development of an approximate relationship that predicts the maximum amplitudes of these MPWs with an accuracy that should be acceptable in engineering design, at least for initial purposes. The formula shows that peak pressure amplitudes decay much more slowly than those from an overground portal, namely varying approximately as r −0.5 compared with r −1, where r denotes the distance from the portal.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-05-19T07:08:34Z
      DOI: 10.1177/09544097221099393
       
  • Multi objective ant Colony Optimisation to obtain efficient metro speed
           profiles

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      Authors: Pablo Martínez Fernández, Juan B Font Torres, Ignacio Villalba Sanchís, Ricardo Insa Franco
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      Obtaining efficient speed profiles for metro trains is a multi-objective optimisation problem where energy consumption and travel time must be balanced. Automatic Train Operation (ATO) systems may handle a great number of possible speed profiles; hence optimisation algorithms are required to find efficient ones in a timely manner. This paper aims to assess the performance of a particular meta-heuristic optimisation algorithm, a variation of the traditional Ant Colony (ACO) modified to deal with multi-objective problems with continuous variables: MOACOr. This algorithm is used to obtain efficient speed profiles in up to 32 interstation sections in the metro network of Valencia (Spain), and the convergence and diversity of these solution sets is evaluated through metrics such as Inverse Generational Distance (GD) and Normalised Hypervolume (NH). The results are then compared to those obtained with a conventional genetic algorithm (NSGA-II), including a statistical analysis to identify significant differences. It has been found that MOACOr shows a better performance than NSGA-II in terms of convergence, regularity and diversity of the solution. These results indicate that MOACOr is a good alternative to the widely used genetic algorithm and could be a better tool for rail operation managers trying to improve energy efficiency.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-05-18T06:50:37Z
      DOI: 10.1177/09544097221103351
       
  • Redefining rail systems verification and validation: The safety/security
           STAIRCASE model

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      Authors: George Bearfield, Coen Van Gulijk, Richard James Thomas
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      Safety critical functions of the engineered railway need to perform at levels of integrity that are so high that an acceptable failure rate cannot be demonstrated through testing alone. Where such functions need to be implemented in complex programmable electronic systems certain design, build and test requirements are defined in technical standards and these are deemed to ensure that the correct level of systematic integrity is achieved. These approaches are based on assumptions around how system requirements are managed and delivered which are increasingly challenging to meet in practice. In particular the V&V lifecycle used in functional safety standards and emerging cyber security design standards is idealised. It assumes a top-down cascade of requirements for each delivery project. The approaches have become the de-facto standard internationally and are now mandated to an extent in European railway safety regulations. This paper proposes a different approach: a new lifecycle model that aligns better with the reality of the modern global supply chain and the order in which asset design and project delivery activities are actually undertaken to improve the ability to proactively manage safety.This leads to a fundamental change in the assurance philosophy to bring a simpler and more understandable approach. A framework for applying this approach is set out along with further research objectives to deliver the solution in practice.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-05-17T04:46:46Z
      DOI: 10.1177/09544097221102292
       
  • Wireless sensor nodes for freight trains condition monitoring based on
           geo-localized vibration measurements

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      Authors: Federico Zanelli, Edoardo Sabbioni, Marco Carnevale, Marco Mauri, Davide Tarsitano, Francesco Castelli-Dezza, Nicola Debattisti
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      While rail freight transportation is gradually becoming a crucial asset in the context of decarbonization of the transport sector, new standards and requirements in this field aim at improving the safety and reliability of freight vehicles and the infrastructure. From this perspective, Condition Monitoring and Condition Based Maintenance are becoming essential tools to improve systems reliability through the use of in-service instrumented vehicles. On the contrary of high-speed applications, freight trains are actually not provided with any monitoring systems able to carry out this kind of analyses. In this context, an innovative hybrid monitoring system composed by wireless sensor nodes and a gateway was developed to be suitably mounted on a freight wagon. Sensor nodes, power supplied by solar energy, are able to carry out synthetic indices from vibration measurements, while the gateway acquires correlated GPS and odometry information. In order to take advantage of the acquired data, a software based on a geo-localization algorithm created for high-speed applications was developed in order to correlate vibration data to the railway line mileage. A field campaign allowed to test the system on a real freight wagon and to acquire many experimental data. Using the collected experimental data, in the paper is shown how the developed software can be used to perform diagnostic activities of the infrastructure. Moreover, it is demonstrated that relying on the only GPS information is sufficient to get enough accurate georeferenced data for freight trains applications. This paves the way to the future development of a completely wireless system able to perform condition monitoring of both the vehicle and the infrastructure minimizing the impact on the vehicle.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-05-16T07:48:27Z
      DOI: 10.1177/09544097221100676
       
  • An experimental study on abnormal vibration of metro trains caused by
           out-of-round wheels

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      Authors: Jintian Wang, Xin Ding, Zhendong Liu, Wanxiu Teng, Tao Liu, Yongsheng Li
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      Out-of-round (OOR) wheel often happens to trains, which can cause abnormal vibration. To develop effective countermeasures to minimize the abnormal vibration, it is necessary to study how the wheel OOR wear affects the vehicle vibration. This paper performs an experimental study on the abnormal vibration characteristics of metro trains with out-of-round wheels. The vibration characteristics is identified by the general survey of wheel roughness from special tests. The statistic wheel wear values of all the vehicles in an operating metro lines are studied to investigate the relationship between the wheel wear and the operating mileage. Several re-profiling strategies are implemented to eliminate the abnormal vibration caused by wheel OOR. The results show that the root cause of the abnormal vibration and deterioration of ride comfort is the car-body flexible resonance excited by the wheel OOR wear. Wheel re-profiling is the most effective measure for reducing the vehicle abnormal vibration. By re-profiling all the wheels of a tested metro vehicle, the ride comfort can be improved by 35% ∼ 40% and the axle-box acceleration can be reduced by 40%.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-05-13T12:22:19Z
      DOI: 10.1177/09544097221102286
       
  • Numerical investigation of the slipstream characteristics of a maglev
           train in a tunnel

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      Authors: Zhen Liu, Dan Zhou, David Soper, Guang Chen, Hassan Hemida, Zijian Guo, Xianli Li
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      High-speed maglev trains operate at higher speeds than conventional high-speed trains. This has implications on intensified aerodynamic issues, such as the transition between open air running and entering into a tunnel. In this paper, numerical simulation of a maglev train entering a tunnel is carried out using IDDES methods (based on SST k-omega model) to analyze the changing slipstream. The peaks and fluctuations of the slipstream are analyzed, together with the transient wake characteristics and TKE (turbulent kinetic energy) distributions. The influence of train nose length on the slipstream and its associated characteristics inside tunnels is also investigated in this paper. It was found that as the maglev train enters the tunnel, the wake slipstream at measuring points close to tunnel entrance increases significantly then decreases slightly with the increase of distance to tunnel entrance. Overall, the fluctuation and magnitude of slipstream inside tunnel is larger than that on open line, more specifically, the maximum TKE generated inside tunnel is. 7.62% larger than that on the open line at contour X = 3 H behind the train tail. Besides it takes longer time for the slipstream inside tunnel to return to the initial condition. These phenomena could be explained by that the scale of vortex structure formed behind the train tail is larger, the developing distance of the wake vortices in the streamwise direction is longer and the TKE generated is more significant inside tunnel. It was also found that increasing the nose length could effectively decrease the spatial scale and TKE of the wake vortices, which resulted on reducing the peak and pulsation of wake slipstream. Comparing to that of 5.4 m, the peak of the wake slipstream of the maglev trains with the 7.4 m and 9.4 m nose lengths at Y = 0.235 m(0.385) is reduced by approximately 23.7%(58%) and 35.9%(82.2%) on open field, and by about 3.6%(4.7%) and 14%(18.5%) inside tunnel. Besides, the maximum TKE at contour X = 2H/3H/5H behind the train tail decreases about 14.4%/10.7%/11.3% and 51%/31.5%/18% as the nose length increase to 7.4 m and 9.4 m respectively.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-05-13T11:09:04Z
      DOI: 10.1177/09544097221100658
       
  • Use of deep convolutional neural networks and change detection technology
           for railway track inspections

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      Authors: Ryan M Harrington, Arthur de O Lima, Richard Fox-Ivey, Thanh Nguyen, John Laurent, Marcus S Dersch, J Riley Edwards
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      Railroad track inspections conducted in accordance with federal regulations and internal railway operating practices result in significant labor costs and occupy valuable network capacity. These factors, combined with advancements in the field of machine vision, have encouraged a transition from human visual inspections to machine-based alternatives. Commercial machine vision technologies for railway inspection currently exist, and automated analysis approaches—which deliver objective results—are available in some systems. However, they are limited to a “pass/fail” approach through the detection of components which fail to meet maintenance or geometry thresholds, as opposed to being able to detect subtle changes in track conditions to identify evolving problems. To overcome these limitations, this paper presents results from the field deployment and validation of a system that pairs three-dimensional (3D) machine vision with automated change detection technology. The change detection approach uses a deep convolution neural network (DCNN) to accurately characterize track conditions between repeat runs. Current automated track inspection technologies were studied, and the applicability of change detection is discussed. The paper presents the process for 3D image capture, DCNN training, and evaluation by comparing DCNN results to an expert human evaluator. Finally, it presents change detection results for fastener presence and spike height. Results indicate that this technology can successfully identify fasteners and spikes with percent accuracies greater than 98% and that it can successfully generate change detection results for comparison of track condition among runs.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-05-12T06:59:40Z
      DOI: 10.1177/09544097221093486
       
  • Simulation of the inherent structural irregularities of high-speed railway
           turnouts based on a virtual track inspection method

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      Authors: Xu Sun, Ping Wang, Jingmang Xu, Fei Xu, Yang Gao
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      Track geometry parameters measured by a track recording car at a turnout are often hard to interpret due to the concomitant geometric complexity, especially for a high-speed railway turnout whose running edge is not interrupted. The virtual track inspection (VTI) method integrated with a multibody system model is proposed to reveal the longitudinal level and alignment of high-speed railway turnouts when the train passes in the main line and in the branch line. Firstly, the principle of inertial measurement and its implementation in MBS are introduced. Then, the VTI method is applied to the vehicle-turnout dynamics using a single-layered co-running track model and validated on tangent and curved tracks in the spatial and wavelength domain. Zero-phase Filters for wavelength ranges 3–25 m and 1–5 m are necessary to eliminate interference from long waves, and to better identify the switch and crossing, respectively. Finally, the effect of different track foundations is studied, including the two-layered co-running track model and the finite element model on the VTI method.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-05-06T01:56:27Z
      DOI: 10.1177/09544097221092616
       
  • Evaluation of locomotive frame and fuel tank gusset modifications to
           prevent fatige cracks

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      Authors: John P Wachsmuth, Brent S Ballew
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      Fatigue cracks have been detected in the underframes, fuel tanks, and fuel-tank gussets of some diesel locomotives that are currently in service. This presents the risk of a fuel tank separating from its locomotive and has an associated cost for making repeated repairs. It is therefore an interest to both operators of locomotives and to the designers of future locomotive models to understand the root cause of the cracks and to determine an effective remedy. In order to accomplish these goals, a finite element analysis (FEA) was used to identify events in the service environment that are capable of driving crack growth at a frequency that roughly matches the observed interval between crack repairs. These events were then used in further FEA simulations to predict the efficacy of various proposed remedies. It was found that the fuel tank, engine, and alternator of a locomotive behave as structural elements that resist deformations in the underframe. This explains why locomotive models with a relatively large fuel tank when compared to their engine and alternator are particularly susceptible to developing cracks: they experience higher stresses on their fuel tank and supporting brackets. It was also found that the most effective remedies were those that mitigate stress concentration effects from the gusset's rectangular design.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-05-04T07:02:48Z
      DOI: 10.1177/09544097221092934
       
  • Static and dynamic effects of train-track-bridge system subject to
           environment-induced deformation of long-span railway bridge

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      Authors: Zhaoling Han, Shengyang Zhu, Wanming Zhai, Bin Zhu
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      Laying ballastless tracks on a long-span railway bridge with a main span greater than 300 m is a challenge in engineering practice and has aroused significant concerns. Influenced by complicated environmental factors, long-span railway bridges in service deform with large amplitudes and complex shapes, which may result in damage to the track structure and threaten the running safety and ride comfort of trains. In this study, we investigate some typical statics and dynamics problems under the actual conditions of a long-span cable-stayed high-speed railway bridge with a main span of 400 m and laying ballastless track. The track-bridge finite element model and dynamic interaction model of the train-track-bridge system are first established. Furthermore, the influences of the complicated environment-induced bridge deformations are comprehensively investigated using the curvature method that reveals the deformation compatibility of the bridge-track system and indicates the dynamic interaction behavior of the train-track-bridge system subject to train running speeds and bridge deformations. Results indicate that excellent dynamic performance of the train-track-bridge system can be achieved by setting an elastic cushion of 0.1 N/mm3 under the track bed. Interface damage between track layers will not occur directly because of the complex deformations of the bridge decks. The bridge deformations induced by the environmental temperature and the concrete creep are qualified. The dynamic responses of the train-track-bridge system are also excellent under the excitations of bridge deformations. Dynamic simulations of the train-track-bridge system are proposed to evaluate long-span bridge deformations subject to complicated service situations in comparison with an oversimplified statics evaluation.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-04-30T09:39:09Z
      DOI: 10.1177/09544097221095260
       
  • A tool for rapid simulation and sizing of hybrid traction systems with
           fuel cells

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      Authors: Luca Pugi, Lorenzo Berzi, Francesco Cirillo, Alessandro Vecchi, Viola Pagliazzi
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      Diesel multiple units (DMU) offer an affordable alternative to electric trains on lines in which infrastructural and maintenance costs of electrification are not justified. A further improvement of sustainability involves the abandonment of internal combustion engines in favour of an electric power train sustained by an on-board storage system. In this work, the authors propose a model to perform a rapid simulation of hybrid storage systems based on hydrogen fuel cells,a technology that should be complementary with respect to battery-operated trains. The proposed tool is applied, as a benchmark test case, to a modular passenger train devoted to regional service. Obtained results clearly demonstrate the capabilities of proposed tools and give useful indications for a feasible optimization and integration of fuel cells for railway applications.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-04-30T02:50:15Z
      DOI: 10.1177/09544097221092622
       
  • The role of vehicle dynamics in train-induced ground vibrations and the
           detection of irregular axle-pulse responses due to a varying track support
           stiffness

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      Authors: Lutz Auersch
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      Train-induced ground vibrations are all generated by the vehicle, by static or dynamic vehicle loads. The most important and most accepted excitation are the dynamic wheel loads from the passage over track irregularities. Dynamic wheel loads will be compared from parallel axle-box and ground vibration measurements at more than seven sites. Some low-frequency excitation of ground vibrations, typically between 10 and 30 Hz, cannot be found in the axle-box measurements. Therefore, other vehicle modes, such as rigid bogie modes, flexible carriage modes, rigid and flexible wheelset modes, have been analysed for additional excitation forces. These vehicle dynamics analyses give an explanation for higher axle-box results at high frequencies, but not for the excitation of the higher low-frequency ground-vibration component. Finally, the effect of the moving static train loads will be analysed. For a regular track and soil, the moving static train loads yield the quasi-static response which exists only in the low-frequency nearfield of the track. If the support stiffness is randomly varying along the track, the pulses on the track generate an additional low-frequency component which is called the irregular pulse responses. This component will be demonstrated by numerical analysis where all axle pulses are superposed in frequency domain.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-04-27T09:19:13Z
      DOI: 10.1177/09544097221086064
       
  • A review on cybersecurity in railways

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      Authors: Ravdeep Kour, Amit Patwardhan, Adithya Thaduri, Ramin Karim
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      Digitalisation is transforming the railway globally. One of the major considerations in digital transformation of any industry including the railway is the increased exposure to cyberattacks. The railway industry is vulnerable to these attacks because since the number of digital items and also number of interfaces between digital and physical components in the railway systems keep increasing. Increased number of items and interfaces require new frameworks, concepts and architectures to ensure the railway system’s resilience with respect to cybersecurity challenges, such as lack of proactiveness, lack of holistic perspective and obsolescence of safety systems exposed to current and future cyber threats landscape. To this date, there are several works carried out in the literature that studied the cybersecurity aspects and its application on railway infrastructure. However, to develop and implement an appropriate roadmap to cybersecurity in railways, there is a need of describing emerging challenges, and approaches to deal with these challenges and the possibilities and benefits of these.Hence, the objective of this paper is to provide a systematic review and outline cybersecurity emerging trends and approaches, and also to identify possible solutions by querying literature, academic and industrial, for future directions. The authors of this paper conducted separate searches through four popular databases, that is, Google Scholar, Scopus, Web of Science and IEEE explore. For the screening process, authors have used keywords with Boolean operators and database filters and identified 90 articles most relevant to the study domain. The analysis of 90 articles shows that majority of the cybersecurity studies lies within the railways are conceptual and lags in application of Artificial Intelligence (AI) based security. Like other industries, it is very important that railways should also follow latest security technologies, trends and train their workforce for cyber hygiene since railways are already in digitalization transition mode.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-04-26T07:19:20Z
      DOI: 10.1177/09544097221089389
       
  • A study of vertical tie reaction forces in ballasted railroad tracks
           through field instrumentation and numerical modeling

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      Authors: Md Fazle Rabbi, Radim Bruzek, Theodore R Sussmann, Hugh B Thompson, Debakanta Mishra
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      This manuscript presents findings from an ongoing research study at Oklahoma State University studying different factors that affect vertical tie reaction forces in ballasted railroad tracks. A combined approach involving field instrumentation and numerical modeling has been adopted for this purpose. Measurements of tie reactions can indicate the load distribution patterns and quality of vertical support along a track. Locations where tie support conditions are not adequate can develop geometry defects, ultimately leading to component failure. Three different approaches are adopted in this study to measure the forces being transmitted through the rail-tie interface; this is equal to the tie reaction force. The field instrumentation effort validates an alternative method to measure forces at the rail-tie interface using rail-mounted strain gauges. Results from this approach are compared to two other conventional methods of force measurement, i.e. through the use of load cells (LC), and an instrumented tie plate (ITP). A validated 3-dimensional Finite Element (FE) model is used to support the field-observed trends, and explain any observed discrepancy. Parametric analyses using the FE model identify different factors that can contribute to the rail-tie interaction force, thus affecting the instrumentation results. The strain gauge-based approach, using the concept of differential shear strain measurement, has been established as a suitable method for tie reaction force measurement. Exact measurement of the tie reaction force can be ensured through proper installation of the strain gauges, away from possible boundary effects.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-04-26T06:58:24Z
      DOI: 10.1177/09544097221089406
       
  • A study of wheel wear on a high-speed railway motor car

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      Authors: Hutang Sang, Jing Zeng, Feng Gan, Jian Mu, Yayun Qi
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      Wheel/rail wear is one of the key issues in the safe operation of a high-speed railway motor car. This paper analyzes and predicts the wheel wear evolution of motor car during the long-term operation process. Firstly, the detailed motor car with gear transmission systems and trailer car of the high-speed train, which take into account various non-linear factors such as dampers, bump stops, wheel/rail contact relation, etc., are developed to obtain interaction force between wheel and rail. Secondly, according to the tread update strategy based on fixed travel distance, a novel wheel wear prediction model integrating the Archard wear model and previous dynamics system is established. In order to more accurately obtain the dynamic responses of the motor car, the comprehensive gear transmission system coupling with motor bogie is also built, which considers the time-varying mesh stiffness and gear shift coefficient. And the corresponding traction characteristic curve is also applied to the gear transmission system. Finally, the wheel wear evolution in one re-profiling cycle is simulated to verify the developed model, and the wheel wear mechanism is investigated in detail. Furthermore, the influence of traction velocity on wheel wear is also investigated. The simulation shows that the cumulative wear amount of both two cars increases gradually and the wear rate decreases gradually with traveling mileage, but the wear rate of the trailer car decreases faster than that of the motor car due to larger longitudinal creepage and longitudinal creep force induced by traction torque. Moreover, the max wheel wear depth and wear bandwidth for motor car gradually increase with traction velocity. While the discrepancies of the max wheel wear depth and wear bandwidth for trailer car are small under different speeds.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-04-26T04:24:53Z
      DOI: 10.1177/09544097221096467
       
  • Application of neural networks for the prediction of railway bearing
           failures

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      Authors: Pablo Garrido Martínez-Llop, Juan de Dios Sanz Bobi, Alberto Huera Plaza
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      Bearing overheating and anomalous accelerations are two principal failure modes for this safety component. The supervision of bearing’s behaviour is essential to ensure a safe and reliable operation. A safety component’s failure may cause a speed limitation or even a non-available train for operating, so a predictive maintenance for bearings and other critical components is mandatory for the manufacturers, operators and maintainers in the railway sector. Bearing temperature, exterior temperature, train speed and other variables are measured every second in real time. From all the data collected and stored in the last years some algorithms and models are designed and trained in this paper to detect bearing anomalies 2 days before a real failure is detected and the safety alarm is enabled. The methodology for obtaining the optimal algorithm is exposed. Different artificial neural networks based on different optimization models such as the Mini-batch Gradient Descent (MGD) or Adam optimizer are compared. A final neural network with 10 hidden layers to detect bearing failure is proposed reaching 99% of accuracy, 95% of precision and 90% of sensitivity. The objective of predicting a bearing anomaly with some days in advanced is reached with high precision level, which will lead also to cost savings and a contribution for the sustainability because many inspections could be reduced and the energy cost associated to them.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-04-26T02:17:01Z
      DOI: 10.1177/09544097221084419
       
  • Effectiveness of grouted layer in the mitigation of subway-induced
           vibrations

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      Authors: Javad Sadeghi, Ehsan Haghighi, Morteza Esmaeili
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      As a practical countermeasure against generally destructive subway-induced vibrations, the injection of a continuous thin layer of soft materials into the soil under adjacent receivers is investigated in this paper for the first time. To this aim, simulations were carried out using a finite/infinite element model of a railway track, tunnel, and surrounding soil. A straightforward analytical approach was implemented to model the dynamic excitation of the moving train. In addition, the effect of a soft V-shaped grouted layer on vibration mitigation on the ground was evaluated via a parametric analysis that determined the impacts of soil type, grout specifications, and train speed. The obtained results clearly indicated that a softer isolator (i.e., the grouted layer) in combination with a stiffer soil provides the best configuration for attenuating the subway-induced vibrations. Furthermore, the injection angle and train speed were shown to have minimal impacts on the isolator performance. Other contributions of the present paper include developing a simple equation to estimate the grouted layer effectiveness and describing how the isolator works in layered soils.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-04-25T11:50:11Z
      DOI: 10.1177/09544097221089417
       
  • Field testing and performance optimization of a weld reinforcement device
           in heavy haul railways'

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      Authors: Guangpeng Liu, Hong Xiao, Guangming Shi, Moyan Zhang, Mahantesh M Nadakatti, Mu Gu
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      The Bowed plates weld device (BPWD) is a new type of rail weld reinforcement device, which has been widely applied in heavy haul railway lines in China. It changes the service state and vibration characteristics of a weld. In order to explore the BPWD vibration influence on the track, static, and dynamic on-site tests were carried out on a heavy haul line. The vibration influence and spectrum characteristics of the track between BPWD and unplated weld (UW) was compared. At the same time, a 3D coupling model of heavy haul train-rail weld was established and optimization of service performance of the BPWD was carried out. The results showed that the average acceleration of rail, sleeper and ballast at the BPWDwere 52.7%, 43.5%, and 50.2% lower than that of UW. In comparison with UW, peak value of the periodic frequency spectrum and dominant frequency distribution in the BPWD track structure could be effectively reduced from rails to ballast. Length of 0.8 m for plate was found to be optimum in order to reduce the rail stress effectively. The material of the insulating interlayer should preferably be nylon.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-04-25T11:42:32Z
      DOI: 10.1177/09544097221091041
       
  • Welding simulation of railway bogie frame side beam: Analyses of residual
           stresses, clamping forces, distortion and prediction of fatigue S-N curves
           

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      Authors: Shukri Afazov, Kaylan Mistry, Kamen Uzunov
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      This paper presents numerical analyses of a welding simulation of a bogie frame side beam. The simulation is based on an analytical thermal model coupled with a non-linear structural finite element model using shell elements enabling the welding simulation of large structures. The predicted clamping forces, distortions, and residual stresses for different clamping conditions and plate thicknesses are analysed in terms of manufacture. A new fatigue model based on the endurance limit approach is proposed using residual stresses to predict the S-N curves. The predicted S-N curves with the proposed model showed close correlation with the S-N curves for class F and class F2 welds of the BS7608 standard, demonstrating its validity and potential use in design.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-04-25T02:05:59Z
      DOI: 10.1177/09544097221094986
       
  • Acoustic roughness measurement of railway tracks: Implementation of an
           optical measurement approach & possible improvements to the standard

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      Authors: Florian Mauz, Remo Wigger, Tobias Wahl, Michal Kuffa, Konrad Wegener
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      The measure for assessing the acoustic quality of the rail surfaces, the acoustic roughness, is defined in the EN 15610 standard. It is shown that this standard contains gaps with regard to the applied procedures for processing the raw data to the quantity of acoustic roughness. Additions to the standard appear necessary to ensure better comparability of the results. A piece of rail tactilely measured by METAS (Swiss Federal Institute of Metrology) was used as a reference. Measurement data recorded by a laser triangulation sensor was used to quantify the adjustments to the standard. This paper provides an overview of the individual processing steps and systematically examines possible additions to the standard to improve the quality of the outcome. Special emphasis was given to a method for outlier removal, pre-filtering, spike removal, curvature correction and calculation of one-third octave bands. It becomes apparent that different implementations can have a significant impact on the final result. The filter used, the wavelength ranges, the methodology for removing outliers should be specified. The spike removal, curvature correction and the calculation of the one-third octave bands should be supplemented in detail to reduce ambiguities in the implementation.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-04-24T07:57:15Z
      DOI: 10.1177/09544097221086487
       
  • A finite element modelling approach for the numerical analysis of switch
           rail contact loading and cyclic profile degradation

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      Authors: Dino Velic, Martin Krobath, Erik Stocker, Uwe Ossberger, Johann Gsodam, Werner Daves
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      A dynamic 3D finite element model for the calculation of profile degradation in the switch panel is presented. The model includes the contact between wheel and rail, as well as the contact between switch rail and stock rail to allow an elastic relative movement between the two rails. Break-outs of the switch rail tip can be facilitated by this relative movement and the stresses and strains at this interface are calculated. The profile degradation of the switch rail due to contact loading between wheel flange and switch rail is numerically simulated considering the cyclic plastic deformation of the rail material. The sliding wear is evaluated separately and superimposed to the geometrical change caused by the plastic deformation.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-04-24T02:38:40Z
      DOI: 10.1177/09544097221095694
       
  • Field test for micro-pressure wave reduction measurement by area
           optimization of windows of tunnel hoods

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      Authors: Hidehiko Okubo, Tokuzo Miyachi, Takashi Fukuda
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      The air compression of a high-speed train entering a tunnel results in micro-pressure waves (MPWs), which can cause environmental problems. To mitigate MPWs, tunnel hoods with discrete windows are installed at the tunnel entrances. By properly adjusting the window conditions, the efficiency of the tunnel hood in mitigating MPWs can be enhanced. Per Japanese convention, window conditions are optimized by changing the opening/closing pattern in the longitudinal direction (pattern optimization). The optimization pattern of the windows is fundamentally different if there is a change in the train speed, train nose length, the relative position between the train and the windows, or the train nose shape. Therefore, for extremely long tunnel hoods, the optimal state of the windows is almost impossible to detect numerically or experimentally using pattern optimization. In this study, we realized a rapid and simple optimization of the windows of the tunnel hood (i.e., area optimization) for mitigation of MPWs by field measurements. The result demonstrated that the area optimization considerably helps in mitigating the MPWs, despite the simplicity of the procedures.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-04-23T08:18:19Z
      DOI: 10.1177/09544097221080368
       
  • An investigation into the influence of wheel–rail contact relationships
           on the carbody hunting stability of an electric locomotive

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      Authors: Wei Li, Qinghua Guan, Maoru Chi, Zefeng Wen, Jianfeng Sun
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      Carbody hunting stability has attracted more and more attention due to its great influence on the dynamic performance of a railway vehicle. To fully understand the correlation between the wheel–rail contact relationship and the carbody hunting stability of an electric locomotive, the wheel–rail contact geometry analysis and the multi-body dynamics simulation are carried out in this work. The focus is on the influences of track parameters (including rail profile, rail cant and track gauge) on wheel–rail contact relationships and carbody hunting stability. A group of rail profiles are obtained by interpolating between the standard CHN60 profile and the worn rail profiles. The nominal equivalent conicity, the effective equivalent conicity and the wheel–rail contact bandwidth for a wheelset lateral displacement of ±6 mm are used to evaluate the wheel–rail contact relationship, while the lateral continuous comfort index is used to evaluate the carbody hunting stability. The simulation results show that keeping the rail cant at about 1/40 and reducing the track gauge and the wear depth at the gauge corner of rail can improve the carbody hunting stability of the electric locomotive. Furthermore, the effective equivalent conicity is a good choice to establish the relationship between the wheel–rail contact geometry and the carbody hunting stability.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-04-23T06:11:36Z
      DOI: 10.1177/09544097221084412
       
  • Finite element investigation of residual stresses during laser powder
           deposition process as an innovative technique to repair worn rails

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      Authors: Ershad Mortazavian, Zhiyong Wang, Hualiang Teng
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      In recent years, a great deal of effort has been made to use laser powder deposition (LPD) as a novel way of repairing damaged metal components. Minimizing the residual stress in the LPD process to prevent premature failure and delamination is very important, so the proper deposition material and technique must be used. This paper studies the use of the LPD process to repair a standard U.S. light rail by building up multiple deposition layers onto the worn railhead. The investigation of the rail repair process was performed through the systematic finite element modeling of the multi-layer LPD process using the element birth-and-kill technique. In this technique, the effects of the type of deposition material and the preheating temperature on the magnitude and distribution of the residual stresses were studied. The candidate deposition steels included 304L stainless steel, 410L stainless steel, Stellite 6, and Stellite 21, each one of which was explored separately. To analyze the effect of preheating, various temperatures, that is, 25°C, 400°C, 600°C, 800°C, and 900°C, were set as the initial temperatures of the railhead. Ultimately, it was shown that preheating has a significant effect in minimizing the residual stresses. It was found that each increase in the preheating temperature resulted in an overall decrease of the residual stresses by 25%–30%. In addition, Stellite 21 was identified as the most promising deposition steel in terms of giving the least risk of failure and delamination.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-04-22T10:46:54Z
      DOI: 10.1177/09544097221089410
       
  • A vision for a lightweight railway wheelset of the future

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      Authors: Stefano Bruni, Preetum J Mistry, Michael S Johnson, Andrea Bernasconi, Michele Carboni, Davide Formaggioni, Guido Carra, Sergio Macchiavello, Edoardo Ferrante, Ingo Kaiser, Jordi Viñolas, Irene Marazzi
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      Rail vehicle lightweighting using fibre reinforced polymer composite materials is essential for the future of rail. This is recognised as a means of reducing carbon dioxide production through lower energy consumption, as well as reducing the impact on track degradation, thus delivering improved rail capacity and performance. This paper presents an overview of the work conducted within work package three of the NEXTGEAR project focused on the ‘wheelset of the future’. Three concepts for a hybrid metallic-composite railway axle are proposed and their strengths and weaknesses are assessed. A finite element analysis on the selected concept was conducted, including a solution for the bonded joints of the metallic collars which provide the interface to the wheels and bearings. An axle mass reduction of over 63% was shown. An overview is also provided regarding the analysis of manufacturability of the axle, non-destructive methods for axle inspection/structural health monitoring and effects of impacts from ballast stones. Finally, a preliminary evaluation of the benefits arising from the reduction of the unsprung masses is provided, based on multibody simulations of vehicle dynamics.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-04-19T03:14:56Z
      DOI: 10.1177/09544097221080619
       
  • Detection of rail local defects using in-service trains

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      Authors: Morad Shadfar, Habibollah Molatefi
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      As track components deteriorate, their interaction dynamic response will alter accelerations on the train. Measuring acceleration on train components is a method to conduct condition monitoring of track defects. The measured signal can be used for the detection of rail surface defects which implement impacts on measured accelerations. In this paper, the axle-box acceleration (ABA) is measured in a subway as a case study. Fourier transform (FFT), empirical mode decomposition (EMD) and ensemble EMD (EEMD) methods are used to study accelerations relative to the track. Wheel frequencies are calculated using finite element method (FEM) to determine frequency couplings. Velocity-dependent/independent components and source of excitation of the measured signal are distinguished. Results indicated that the FFT approach can be applied for both velocity-dependent and velocity-independent vibration components for frequencies up to 680 Hz. Also, the EEMD method can be used to distinguish the impact component of the measured signal.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-04-19T02:25:08Z
      DOI: 10.1177/09544097221076253
       
  • Theoretical model of fatigue limit of full-size axle with different impact
           defects

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      Authors: Suxia Zhou, Suyu Duan, Yi Wu, Yuduo Sun, Zhang Zhao
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      The impact defects on the surface of the axles of high-speed trains may cause hidden dangers to the safe operation of the trains. In order to study the influence of different shape defects on axle fatigue limit, the method of combining finite element simulation and fatigue test is adopted. According to the statistics of the foreign object damage impact defect of the axle in the workshop, impact defects were prefabricated on the axle specimen surface, stress analysis of the impact defect area was carried out, and then the more dangerous defect shape was obtained. Fatigue tests were carried out on prefabricated axle specimens. The P-S-N curves of each specimen group were fitted by the approximate Owen one-side tolerance limit method. In line with the fatigue test results of samples, considering the factors such as axle surface mass coefficient, size effect coefficient and load type, to ensure the security of the train operation, fatigue strength safety factor Sσ is introduced to establish a full-size axle fatigue prediction mathematical model. The fatigue limit of full-size axle with impact defects was predicted and the accuracy of the model was proved. Finally, on the basis of the defect shape, the modified EI Haddad model was used to fit the two-parameter theoretical model of defect depth and full-size axle fatigue limit, the standards were combined for safety assessment.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-04-19T01:34:44Z
      DOI: 10.1177/09544097221086077
       
  • Quantitative fatigue evaluation of complex welded connections and
           application in a train traction motor frame component

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      Authors: Chen Bingzhi, He Zhengping, Pingsha Dong, Shaopin Song, Zhao Wenzhong
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      Welded connections are common in rail vehicle structures and associated equipment. It is well known that fatigue behaviors of welded structure are controlled by fatigue capability of welded joints. Although there exists numerous joint design guidance in Codes and Standards as well as best practices, they are largely empirical and difficult to apply in fatigue assessment of complex joints. In this paper, we adopt a mesh-insensitive structural stress method recently stipulated by ASME Code for fatigue evaluation of pressure vessels and piping components. Starting with stress concentration evaluation of two typical, but complex welded connections of relevance to some rail vehicle structures, we examine how the joint design principle inferred from the two examples can be effectively applied to an actual traction motor frame design and its effective fatigue improvement method. The experimental validation process is also presented for the proposed fatigue improvement technique.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-04-19T01:04:55Z
      DOI: 10.1177/09544097221085329
       
  • Research on the working performance of fouled ballast bed under the
           multi-scale effect

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      Authors: Xianmai Chen, Nan Chen
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      In order to explore the influence of different particle size gradations of dirty materials on the service performance of the ballast bed, the clean track bed, the completely fouled ballast bed polluted by coarse coal and fine coal, respectively, were studied based on the discrete element method. In order to explore the influence of the multi-scale particle size gradation of the dirty material on the service performance of the ballast bed, the clean ballast bed, the completely dirty ballast bed polluted by coarse-particle coal, and the completely dirty ballast bed polluted by coarse-particle coal were simulated, respectively, based on the discrete element method, which are used to analyze the dynamic response of track bed under different working conditions under cyclic load. The model is verified by the lateral resistance and vertical stiffness of the ballast bed to prove the accuracy of the discrete element model. On this basis, the dynamic cyclic load is considered to analyze and study the mechanical response and change law of the ballast bed with different degrees of contamination. Studies have shown that after the ballast bed is contaminated, its lateral resistance and vertical support stiffness are reduced, the amount of settlement increases, the coordination number between ballasts is declined, and the fine-grained dirty material has a worse effect on the ballast bed; The displacement value of the ballast particles decreases with the increase of the depth of the ballast bed; The displacement value of the ballast particles under the rail is the largest, and the ballast particles on the ballast shoulder appear dilatancy; The displacement of the ballast particles at the laterally symmetrical position of the track structure is close to but not completely same; Dirty materials aggravate the frequency of ballast particles, and the impact of fine-particle coal powder is particularly significant.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-04-19T01:00:29Z
      DOI: 10.1177/09544097221086072
       
  • An Empirical analysis of freight train derailment rates for unit trains
           and manifest trains

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      Authors: Zhipeng Zhang, Chen-Yu Lin, Xiang Liu, Zheyong Bian, C Tyler Dick, Jiaxi Zhao, Steven Kirkpatrick
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      Rail is a safe and efficient mode of transporting hazardous materials (hazmat). In the past decade, the hazmat traffic transported by unit trains has significantly increased in the United States. As a result, a comprehensive understanding of the safety and risk of hazmat unit trains is important and can contribute to the identification, evaluation, and implementation of risk mitigation strategies. Limited prior research has focused on unit train derailment risk analysis. This paper develops a quantitative analysis of freight unit train derailment characteristics and compares those statistics to non-unit, manifest trains (mixed trains). Mainline freight train derailment data on Class I railroads between 1996 and 2018 were analyzed for hazmat unit trains, non-hazmat unit trains, and manifest trains. Derailment rates, measured by three traffic exposure metrics (train-miles, ton-miles, and car-miles) were estimated and compared. The analyses showed that a unit train has a 30% lower derailment rate in terms of ton-miles and car-miles than manifest trains, while the derailment rate per million train-miles of unit trains is slightly greater than that of manifest trains. Loaded unit trains have roughly four-fold higher derailment rate in terms of train-miles and car-miles than that of empty unit trains. Within loaded unit trains, hazmat unit trains have lower derailment rates than non-hazmat unit trains. Overall, heavier and shorter loaded unit trains tend to have greater derailment rates in terms of all three traffic exposure metrics. A causal analysis was also conducted for the three types of train. Infrastructure causes were the most frequent in all train types and length followed by equipment-related causes. These statistics provided important information for rational allocation of risk mitigation resources to improve rail hazmat transportation safety.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-04-15T04:58:37Z
      DOI: 10.1177/09544097221080615
       
  • Effect of dynamic stiffness of fasteners on vibration and acoustic
           radiation of a ballastless track

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      Authors: Han-Wen Xu, Jian Han, Xin-Biao Xiao, Xiao-Long Liu, Mou-Kai Liu, Xue-Song Jin
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      A new model for a single wheel rolling over a metro ballastless track is developed. It is used to carry out the analysis on the effect of dynamic characteristics of fastener on the vibration and noise radiation of the wheel and the track in the vertical direction, under the excitation of the wheel/rail uneven surfaces in detail. In this analysis, a rail is modeled as a Timoshenko beam resting on discrete rubber booted short sleepers, and the sleepers are connected with the slab through linear springs and damping units, the slab is modeled by using the FE method, the fastener is characterized by using the Poynting-Thomson model which takes into account that the stiffness and dumping of the fasteners vary with vibration frequency in their service. The dynamic characteristics of the fastener include the variation of its stiffness and damping with frequency. The analysis considers that the fastener dynamic stiffness increases with the excitation frequency while its damping decreases. The vibration and acoustic radiation of the wheel/track is, to varying degree, affected by the dynamic property of the fastener. The vibration and acoustic radiation of the sleeper and the slab is greatly affected by the dynamic property of the fastener. But the effect of the total noise level of the wheel and the track by the dynamic property of the fastener is not so large because the wheel and rail noise is dominant in the whole analyzed system. These conclusions have certain reference values for the study of the vibration and noise reduction measures of the wheel and track coupled system using the fastening characteristic.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-04-07T01:33:16Z
      DOI: 10.1177/09544097221080605
       
  • Effect of rotor eccentricity on the dynamic performance of a traction
           motor and its support bearings in a locomotive

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      Authors: Yuqing Liu, Zaigang Chen, Xia Hua, Wanming Zhai
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      Rotor eccentricity is a common fault of traction motors during operation. To ensure the stability and safety of the traction motor, it is essential to analyze the effect of rotor eccentricity on the dynamic performance of the traction motor, particularly the motor bearings. This study focuses on the extraction of the fault vibration features of a locomotive in the presence of rotor eccentricity under complex internal and external excitations from the traction power transmissions and wheel-rail interactions. A spatial locomotive-track coupled dynamics model with an eccentric rotor motor is applied in this study, and the detailed mechanical structures of the traction motor and motor bearings are comprehensively considered. The results indicate that rotor eccentricity can deteriorate the vibration conditions of the traction motor and intensify the interactions between the components of the motor bearings. Due to the effect of the time-varying mesh forces, the variation in the loaded region of the non-driving end bearing is more significant than that of the driving end bearing.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-03-28T06:43:55Z
      DOI: 10.1177/09544097211072335
       
  • Carrydown of liquid friction modifier

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      Authors: Hatef Rahmani, Dmitry Gutsulyak, Louisa Stanlake, Boris Stoeber, Sheldon Green
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      A small-scale laboratory apparatus was built to study liquid friction modifier (LFM) behavior in a top-of-rail application. A field experiment was also carried out to complement the laboratory findings. KELTRACK® (a water-based LFM) was used as the test fluid. Laser-induced fluorescence served to measure the LFM thickness left on the track after the passage of the wheel. The lab experiments show that the LFM cannot withstand the high wheel-rail contact pressure in the nip present in cargo rail situations. As a result, the liquid is squeezed out laterally and attaches to the edges of the wheel contact band. This “edge liquid” is then carried down the track on the wheel. Gravimetric measurements of the wheel contact band confirm this observation, and show that only a minute amount of liquid is carried through the nip in the valleys between surface roughness features. In the field experiment, the LFM is applied from a trackside unit on a tangent section of the track. About 500 m downstream of the application point, the track has a curved section. LFM cannot be detected anywhere on the track a short distance (∼200 m) past the application unit. However, LFM is detectable on the curved sections of the track up to approximately 2 km from the application unit. This LFM on the curved track is believed to be due to transfer of the “edge liquid” from the wheel to the track, caused by the movement of the contact band as the train rounds a curve. The presence of LFM on the curved track far downstream is consistent with prior measurements of reduced lateral force on the curved track downstream of LFM application sites.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-03-25T10:34:32Z
      DOI: 10.1177/09544097221076258
       
  • An authorisation framework for actively controlled running gear

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      Authors: Roger Goodall, Riccardo Licciardello, Peter Hughes, Rickard Persson
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      A Shift2Rail funded research project called RUN2Rail has investigated a range of new technologies for railway rolling stock. The project included a task on the use of active suspensions, and one of the subtasks was to propose a strategy supporting the authorisation by safety authorities for highly innovative mechatronic vehicles to be placed on the market. The incorporation of electronics and control into suspension systems is still at an early stage, so this paper provides a framework for a practical and efficient authorisation strategy, primarily based upon existing European regulations and standards but in general applicable worldwide.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-03-01T02:33:04Z
      DOI: 10.1177/09544097211066373
       
  • Analysis on new semi-active control strategies to reduce lateral
           vibrations of high-speed trains by simulation and hardware-in-the-loop
           testing

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      Authors: Yiwei Zhao, Yongqiang Liu, Shaopu Yang, Yingying Liao, Zuchen Chen
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      In order to further reduce the vibration of vehicles and simultaneously increase ride comfort, a class of new control strategies, namely, the extension of Rakheja-Sankar (RS) control, is proposed for semi-active suspension systems with magnetorheological (MR) dampers of high-speed trains. At first, the design and analysis of semi-active control strategies are conducted in a quarter railway lateral model considering the node stiffness. Secondly, a whole vehicle model of a high-speed train is constructed by using Universal Mechanism (UM) software to be applied in evaluating semi-active control strategies. Finally, a hardware-in-the-loop (HIL) test system is carried out to verify the performance of the new control strategies. During these processes, the transmission characteristics are calculated and compared, which helps to test the performance of the semi-active control strategy on train vibration suppression. Then, the effect of the control strategies on the dynamic performance of the whole vehicle is studied. The ride comfort under different control strategies is compared, and the effects of different semi-active control strategies on the lateral stability and safety of trains are also analyzed. Through simulations and experiments, it is confirmed that the new control strategies can effectively reduce the lateral vibration of trains and therefore contribute to the improvement of ride comfort while they do not significantly reduce the train running stability and safety. Therefore, the new control strategies possess future application value.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-02-26T02:40:52Z
      DOI: 10.1177/09544097211059042
       
  • Validation of a rail temperature model with experimental measurements

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      Authors: Paulo AG Piloto, Ary VN Frigeri, Manuel Minhoto, Dyorgge A Silva
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      Rail temperature is a key factor when studying the effects of thermal buckling. Many models have been developed to simulate rail temperatures under various weather conditions. This work is based on the model developed by the Chungnam National University (CNU), which includes the shadow effect on the rail and the solar position to improve the temperature prediction during several periods of the day, validates it with experimental data, and compares it with a finite element model. Furthermore, a python library is developed based on the lumped thermal model with small adaptations, called railtemp. The python package has slightly better performance over the original CNU model, reaching a correlation factor R2 of 0.947 and a root mean square error of 2.6°C. Furthermore, a new proposal is presented to determine the temperatures on rail tracks based on air temperature.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-02-25T01:58:59Z
      DOI: 10.1177/09544097221074782
       
  • A vision-based method for line-side switch rail condition monitoring and
           inspection

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      Authors: Jiaqi Ye, Edward Stewart, Qianyu Chen, Lei Chen, Clive Roberts
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      In railway systems, switch rails are one of the key components of switches & crossings (S&C). They are controlled by switch machines to guide trains from one track to another. Due to the discontinuity in geometry, switch rails are exposed to high-impact loads as train wheels pass through. The long-term impact loads can cause local plastic deformation. These faults, and general alignment changes, can lead to the development of a gap between the switch rail and the stock rail known as a toe gap, as well as non-optimal contact with the wheel flange, both of which can endanger the safe operation of passing trains. Currently, periodic visual inspection is the main method for detecting these defects. This is not efficient or reliable enough to support the ever-shortening maintenance windows available in modern railway systems. The development of computer vision technologies and constantly improving processors make it possible to monitor the health status of such safety-critical components in real time. This research proposes a line-side condition monitoring approach for the switch rail. With the use of dedicated identification algorithms, the status of the switch rail, including movement, position, toe gap and the edge of the toes, can be monitored remotely in real time. This approach has been tested in a high-speed train testing centre in China. The results show a capability to further improve the safe operation of S&C while simultaneously reducing the cost and increasing the safety of inspection.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-02-17T06:07:21Z
      DOI: 10.1177/09544097211059303
       
  • Optimization of metro wheel reprofiling based on cluster analysis

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      Authors: Zonghui Lin, Zhenggang Lu, Xinjian Yong, Juyao Wei, Xiaochao Wang
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      According to the characteristics of the metro vehicles running on the same track leading to a similar wheel wear, a clustering method based on k-means is proposed. The weighted wheel flange height of Sh and qR, and wheel flange thickness of Sd are used as clustering parameters. This paper classifies the treads of the wheels to be repaired and obtains a typical worn wheel profile to reprofile the wheels. Under the premise of ensuring the operation safety of vehicles, the wheel profile optimization model is established for a typical worn wheel profile based on the minimum repair volume. The optimized profile is used as the reprofiling template for all wheels in the same classification. Finally, based on the reprofiling standard for the wheel diameter difference between the left and right wheels, the optimization reprofiling of the wheel profile is achieved. The research results show that the proposed optimization strategy base on cluster analysis can significantly reduce the material removal.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-02-02T10:44:22Z
      DOI: 10.1177/09544097211061917
       
  • Development of metro track geometry fault diagnosis convolutional neural
           network model based on car-body vibration data

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      Authors: Zhipeng Wang, Rengkui Liu, Futian Wang, Yuanjie Tang
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      Traditional track geometry fault diagnosis methods, such as track geometry car, track detection trolley and manual measurement, suffer from low detection frequency. Therefore, using vibration data from in-service metro vehicles to diagnose metro track geometry faults can improve the efficiency of metro track condition detection. Hence, a metro track geometry fault diagnosis model using car-body vibration was established in this study based on a convolutional neural network model, and the effects of the structural hyperparameters on the model performance were analysed. First, the problem of car-body vibration data collection was addressed, and a mileage-locating model without the global navigation satellite system was developed. Then, the metro track geometry fault diagnosis model was derived using a convolutional neural network whose architecture is determined by four hyperparameters. Finally, a case study was performed using the Beijing Subway 1 track geometry car detection data and car-body vibration data. The results demonstrated the effectiveness of the proposed model.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-01-29T05:13:57Z
      DOI: 10.1177/09544097221080366
       
  • A review of snow melting and de-icing technologies for trains

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      Authors: Liang Zhou, Liang Ding, Xian Yi
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      Train icing may cause a series of problems to the safety of railway transportation in high and cold regions. Some important technologies on solving this issue are discussed in this paper, with the latest research landscape provided and the future development opportunities suggested. The hazards and principles of train icing are explained firstly, followed by a summary of several available methods of snow melting and de-icing, with their application and shortcomings indicated. The research progress of some basic issues such as the snow conditions of bogie parts and the optimal design of snow protection are discussed and analysed in detail. However, the problem of snow and ice accumulation during train operation has not been completely solved with the existing methods. At the end of this pager, suggestions on snow-resistance technology for trains are proposed for future study and development.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-01-27T07:24:41Z
      DOI: 10.1177/09544097211059631
       
  • A small-distributed aerodynamic brake prototype and its effects on the
           vertical dynamics of high-speed electromagnetic suspension maglevs

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      Authors: Jingjing Weng, Chun Tian, Tianhe Ma, Mengling Wu
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      Aerodynamic braking is a clean and environmentally friendly braking mode, and it does not use mechanical friction as its braking force. In this study, we discuss the development of a small-distributed aerodynamic brake prototype and its structure, working principle, ground test and test results. A computational fluid dynamics (CFD) method is developed to record the aerodynamic forces of the prototype, and the simulation results are validated with the wind tunnel test. On the basis of the CFD simulation, the panel opening and braking processes are modelled to analyse the vertical dynamic characteristics of a high-speed electromagnetic suspension maglev with aerodynamic brakes. In addition, a vehicle, guideway and levitation controller are modelled. Finally, a three-car system dynamic model is used to study the effects of the opening time, initial braking position and feedback gains. The aerodynamic forces of the first car show the most significant changes when the braking panels are opened. The increase in the longitudinal force is 15 461.16 N, and the vertical force varies from a lift force of 35 342.98 N to a downforce of 40 721.35 N. The maximum guideway deflection decreases as the opening time increases. The difference between the deflections recorded at the opening time of 0.064 s and 0.6 s is 1.2 mm. Furthermore, the vertical acceleration decreases as the opening time increases. The condition under which the vehicle brakes when the first car enters the object guideway has the maximum effect on the deflection of the guideway. To ensure levitation stability, influenced by the vertical change of the first car, a high feedback gain for the levitation clearance change is required. However, the levitation stability with aerodynamic brakes has low sensitivity to the feedback gains for the observed velocity and acceleration of the system.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-01-27T01:56:51Z
      DOI: 10.1177/09544097211072681
       
  • A review of research into aerodynamic concepts for high speed trains in
           tunnels and open air and the air-tightness requirements for passenger
           comfort

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      Authors: Sandeep Srivastava, Govindu Sivasankar, Gautam Dua
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      India will soon have its first line with trains operating at internationally defined standards of high speed (exceeding 250 km/h). On the MAHSR (Mumbai-Ahmedabad High Speed Railway) corridor modern high speed trains will routinely operate at speeds as high as 200 mph (320 km/h). At high speed, trains are capable of generating significant aerodynamic effects including wind gusts and air pressure changes, which makes it necessary to address HSTs’ aerodynamics during the planning stage of high-speed rail (HSR) lines. The dynamic pressure tightness in train cars is also an important factor in the design of future railway tunnels, together with the medical health criterion and pressure comfort criteria. With increasing speed, the requirements of pressure tightness increases, which are explained and illustrated in this study. The current study is based on prior work done in the field of aerodynamic effects of HSTs, international standards, and design practice followed in existing HSR projects. Effort has been made to bring various studies in one place for ready reference. Parameters such as pressure comfort, optimized distance between center of track, wayside structural design, and tunnel cross-section requirements are explained. Based on the study and established relation by different authors, the pressure difference calculation is done for the MAHSR project for different scenarios, and passenger comfort was deduced. In this study, three major aspects of the aerodynamic pressure effect on the rolling stock and surroundings are examined, and each aspect is discussed distinctly: (1) open-air considerations: pressure effect on wayside structures, (2) open-air considerations: two trains crossing in the open field, and (3) open-air considerations: tunnel phenomenon: pressure wave effects on trains inside tunnels. The present study and a substantial portion of the existing knowledge base can be extrapolated for use in the future guidelines in India. This study examine the resultant pressures on wayside structures, the resultant pressures on adjacent trains, and pressure wave effects in tunnels (associated analyses were performed to determine the appropriate cross-sectional area of the tunnels), respectively. It includes basic aerodynamic concepts, influencing factors, measurement and calculation of pressure between trains, known and potential impacts, mitigations, standards, conclusions, and recommendations.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-01-27T01:44:06Z
      DOI: 10.1177/09544097211072973
       
  • Evaluation of Chinese freight train bearing condition based on
           spatiotemporal feature extraction

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      Authors: Jin Si, Hongmei Shi, Jinsong Yang
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      Bearing failure in freight trains can directly affect operational safety. Therefore, bearing condition evaluation is of practical and critical significance. In this paper, a new method of evaluating the condition of the bearings is proposed based on spatiotemporal feature extraction with bearing temperature data. First, the temperature time series is divided into many sub-sequences with a sliding time window. Second, based on the forms of series anomaly, point anomaly, and pattern anomaly in time series, the spatiotemporal features extraction framework is presented, which combines manual feature extraction with machine learning methods. Specifically, series classification, distribution-based and increment-based outlier detection, model-based time series anomaly detection methods are utilized to extract abnormal features in temporal, spatial, and spatiotemporal dimensions. Third, a penalty vector is constructed by an ergodic accumulation of penalty values for the outliers. And the weights to each element in the penalty vector are allocated using correlation analysis. The penalty vector and the weights are then employed to calculate the bearing health indicator, which can quantify the health condition and determine the severity of the potential fault. Finally, the validity of the proposed evaluation method is verified with on-site historical temperature data of 15,120 bearings on 35 trains, which demonstrates an accuracy of more than 94%. The method can provide early warning for an average of 161 h before hotbox alarms. The results indicate the proposed method can effectively evaluate the bearing condition and provide supportive information for condition-based maintenance.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-01-17T01:05:12Z
      DOI: 10.1177/09544097211061944
       
  • Railway track support condition assessment—Initial developments on a
           vehicle-based monitoring solution through modal analysis

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      Authors: João Morais, Paulo Morais, Carlos Santos, André Paixão, Eduardo Fortunato
      Abstract: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Ahead of Print.
      Nowadays, there are multiple initiatives showing a renewed interest on railway transport of goods and passengers around the world. Thus, an efficient management of railway infrastructures, both at the operational level and in terms of economic profitability, is not only desirable but also corresponds to an area of ongoing research. In order to contribute to these efforts, an alternative and novel methodology to evaluate railway track support conditions is presented here, based on modal analysis of the characteristic frequencies of the multi-element system composed by a railway infrastructure and an instrumented vehicle moving over it. This methodology belongs to the group of vibration-based structural damage identification methods, and is focused on observing the characteristic frequencies of this multi-element system, which can be correlated with changes in the physical properties of the railway infrastructure under analysis. An important feature of the proposed methodology is that it should enable the collection of information regarding the conditions of the substructure of a railway infrastructure. By performing this assessment of a railway infrastructure over its length, and over time by comparing different rides over the same railway stretch, important information can be gathered regarding the support conditions of the track. This paper presents a complete description on the current stage of development of the proposed methodology, along with the theoretical model that serves as the basis to interpret the collected data. Preliminary verification of this methodology is performed through the analysis of two case studies regarding the passage of an instrumented vehicle over two underpasses. The results obtained so far show that the proposed methodology can provide relevant information regarding the support conditions of railway tracks.
      Citation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
      PubDate: 2022-01-06T02:27:38Z
      DOI: 10.1177/09544097211064101
       
 
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