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Proceedings of the Institution of Mechanical Engineers Part F: Journal of Rail and Rapid Transit
[SJR: 0.449] [H-I: 21] [7 followers] Follow

Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0954-4097 - ISSN (Online) 2041-3017
Published by Sage Publications

[757 journals]

Numerical simulation of a bird impact on a composite aerodynamic brake
wing of a high-speed train
- Authors: Jianyong, Z; Xiaoyu, Z, Mengling, W.
  Pages: 223 - 236
  Abstract: Experimental bird strike tests were conducted in which a 2.6-kg dead chicken was projected at a speed of 500 km/h to hit a raised aerodynamic brake wing. The brake wing was fabricated with a sandwich of composite material as its skin and polymethacrylimide foam as its core. Pre-test numerical analyses of bird strikes were performed using the LS-Dyna solver code, an Arbitrary Lagrangian Eulerian model of the bird, and a Lagrangian model of the brake wing. The numerical and experimental results were well correlated, confirming the validity of the finite element model and calculation approach. Finally, bird strikes were conducted on a brake wing extended to 75° and 90° to determine the difference between the two conditions on the basis of effective wind-drag area. Impact, failure after impact and high strength at impact properties were investigated for a composite of carbon and glass fibre laminate.
  PubDate: 2015-02-19T01:33:25-08:00
  DOI: 10.1177/0954409713508109
  Issue No: Vol. 229, No. 3 (2015)
Bayesian semi-parametric analysis for locomotive wheel degradation using
gamma frailties
- Authors: Lin, J; Asplund, M.
  Pages: 237 - 247
  Abstract: A reliability study based on a Bayesian semi-parametric framework is performed in order to explore the impact of the position of a locomotive wheel on its service lifetime and to predict its other reliability characteristics. A piecewise constant hazard regression model is used to analyse the lifetime of locomotive wheels using degradation data and taking into account the bogie on which the wheel is located. Gamma frailties are included in this study to explore unobserved covariates within the same group. The goal is to flexibly determine reliability for the wheel. A case study is performed using Markov chain Monte Carlo methods and the following conclusions are drawn. First, a polynomial degradation path is a better choice for the studied locomotive wheels; second, under given operational conditions, the position of the locomotive wheel, i.e. on which bogie it is mounted, can influence its reliability; third, a piecewise constant hazard regression model can be used to undertake reliability studies; fourth, considering gamma frailties is useful for exploring the influence of unobserved covariates; and fifth, the wheels have a higher failure risk after running a threshold distance, a finding which could be applied in optimisation of maintenance activities.
  PubDate: 2015-02-19T01:33:25-08:00
  DOI: 10.1177/0954409713508759
  Issue No: Vol. 229, No. 3 (2015)
Optimal design of wheel profiles for high-speed trains
- Authors: Cui, D; Wang, H, Li, L, Jin, X.
  Pages: 248 - 261
  Abstract: The high maintenance cost of high-speed wheels due to wear and rolling contact fatigue is a major problem in the commercial operation of high-speed trains in China. In order to understand the wear behavior of high-speed wheels and its influence on the motion stability of high-speed trains, the worn profiles and the work-hardening of the wheels of the CRH3 high-speed trains that operate on the Wuhan–Guangzhou line were monitored in different periods during service; in particular, the influence of hollow wear of the wheel on the lateral acceleration of the bearing-box was investigated in detail. A new wheel profile design method was suggested to reduce the hollow wear by seeking an optimization match of the wheel profiles, the vehicle’s suspension systems, and the wear behavior of wheels in service. The feasibility of the method was verified by numerical simulation using the operation conditions of CRH3 high-speed trains on the Wuhan–Guangzhou line. A new wheel profile was designed using this method. The wheel/rail contact performance and the vehicle’s dynamic behavior resulting from the designed new wheel were investigated in detail and compared with those of the original wheel. The wear behavior of the designed new wheel profile was predicted based on wear data measured on the original wheel. The results show that compared with the original wheel profile, the designed new wheel profile can improve the wheel/rail contact state, reduce the contact stress level, and lower the friction power of wheel and rail. The extent of hollow wear on the new wheel is significantly decreased and the vehicle has improved dynamic behavior when wheelsets with the designed new profile are used. Thus, the period before re-profiling is required can be effectively extended.
  PubDate: 2015-02-19T01:33:25-08:00
  DOI: 10.1177/0954409713509979
  Issue No: Vol. 229, No. 3 (2015)
Utilizing the track panel displacement method for estimating vertical load
effects on the lateral resistance of continuously welded railway track
- Authors: Zakeri, J. A; Barati, M.
  Pages: 262 - 267
  Abstract: The safe operation of continuously welded rail depends on its ability to laterally resist forces generated by vehicles. In recent decades, considerable improvement has been made in increasing the lateral resistance and stability of track. This has been achieved by using elastic rail fastenings, increasing the height and width of the ballast shoulder, and modifying the shape of the sleeper. This paper deals with the effect of the vertical load on the lateral resistance and stability of a railway track using frictional sleepers (with a ribbed underside) in comparison with conventional sleepers (with a flat underside). The test results prove that the vertical load has a significant effect on the increase in the track’s lateral resistance in both types of sleepers; however, it is more effective in the tracks with frictional sleepers.
  PubDate: 2015-02-19T01:33:25-08:00
  DOI: 10.1177/0954409713508937
  Issue No: Vol. 229, No. 3 (2015)
Predicting high-speed train operation conflicts using workflow nets and
triangular fuzzy numbers
- Authors: Wen, C; Li, J, Peng, Q, Li, B, Ren, J.
  Pages: 268 - 279
  Abstract: The dispatching system of a high-speed railway system is the basis that guarantees trains that run at high speed, high density, are secure and have a good punctuality. The prediction of train operation conflicts is the main issue of train operation adjustment. In this paper, we propose the use of workflow nets and triangular fuzzy numbers to study the issues associated with predicting train operation conflicts. The linked lists for conflict prediction are built and used as tools to derive the train running states corresponding to the two operating modes of train workflow nets: the sequential mode and the alternative mode. Based on the current train running status and the triangular fuzzy numbers of times for future activities in train operation, the probabilities of all kinds of train operation conflicts that might occur can be obtained by comparing the possible end times of the workflow nets with the fixed deadlines. Hence, the prediction of train operation conflicts is realized.
  PubDate: 2015-02-19T01:33:25-08:00
  DOI: 10.1177/0954409713509978
  Issue No: Vol. 229, No. 3 (2015)
Dynamic monitoring of railway track displacement using an optical system
- Authors: Pinto, N; Ribeiro, C. A, Gabriel, J, Calcada, R.
  Pages: 280 - 290
  Abstract: With the increases in traffic, axle loads and travelling speed, the dynamic monitoring of railway tracks and structures is becoming more and more important to ensure a high level of safety and comfort. This situation is particularly critical at transition zones where rapid changes of track stiffness occur. This paper presents a contactless system to measure track displacements and its application in an embankment/underpass transition zone, located on the Northern line of the Portuguese railway network where the Alfa Pendular tilting train travels at a maximum speed of 220 km/h. The system is based on a diode laser module and a position sensitive detector (PSD). The PSD receives the laser beam emission and the detection of the centre of gravity of the beam spotlight on the PSD area enables the calculation of the displacement. Before field application, static and dynamic laboratory validation tests were performed in order to evaluate the system performance for different laser to PSD distances, and an accuracy of 0.01 mm was achieved using data acquisition rates of up to 15 kHz. The optical measuring system proved to be an efficient and flexible way to measure absolute and relative rail displacements in the field, enabling the detection of track deformability differences along the transition zone, even for the passage of trains at high speed (220 km/h).
  PubDate: 2015-02-19T01:33:25-08:00
  DOI: 10.1177/0954409713509980
  Issue No: Vol. 229, No. 3 (2015)
An integrated capacity evaluation method for CBTC- system-equipped urban
rail lines
- Authors: Wang, H; Zhao, N, Chen, L.
  Pages: 291 - 302
  Abstract: Communications-based train control (CBTC) is an emerging technology for urban rail transit systems. An integrated method for assessing the capacity of CBTC-system-installed urban rail lines is proposed in this paper. Based on the UIC Code 406 method, the new integrated method includes train movement simulation, timetable construction, test and optimisation. In order to achieve an accurate blocking time, this paper introduces three operational scenarios, namely: consecutive running of trains, entering a station and turn-back at a terminal station. A practical timetable is implemented and optimised by simulating and evaluating the capacity with UIC Code 406. This paper considers Beijing’s Yizhuang metro line in a case study. It is found that a speed limit on the line produces a greater impact on the capacity compared with dwell time and switch speed restrictions. Furthermore, it is noted that a capacity bottleneck can easily occur during the process of entering a station and also during a turn-back operation at a terminal station.
  PubDate: 2015-02-19T01:33:25-08:00
  DOI: 10.1177/0954409713511448
  Issue No: Vol. 229, No. 3 (2015)
The use of sub-modelling technique to calculate vibration in buildings
from underground railways
- Authors: Hussein, M; Hunt, H, Kuo, K, Costa, P. A, Barbosa, J.
  Pages: 303 - 314
  Abstract: In this paper, a method is presented for the calculation of the vibration created in buildings by the operation of underground railways. The method is based on the sub-modelling approach which is used to couple a model of a building on a piled foundation to another model that calculates the vibration generated in the soil in underground railway tunnels. The method couples a building on a piled foundation to the soil at discrete points by satisfying equilibrium and compatibility requirements at those points. The method results in efficient numerical calculations. A two-dimensional frame made of beam elements is used to model the building and its piled foundation. The elements are formulated using a dynamic stiffness matrix which accounts for Euler–Bernoulli bending and axial behaviour. Vibrations created by a train moving in an underground tunnel are calculated using the well-known pipe-in-pipe (PiP) model. The model calculates the power spectral density (PSD) of the displacement in the soil. The excitation mechanism is the roughness of the rail and the PSD is calculated for a train moving on a floating-slab track in an underground railway tunnel for a stationary process. The current version of PiP accounts for a tunnel embedded in a half-space. The building frame is coupled in this paper at 90° to the tunnel’s centreline. The main result of this paper illustrates the significant contribution of the building’s dynamics to the displacement wave field received by the building. The example presented in this paper shows a decrease of more than 20 dB in the displacement PSDs at frequencies larger than 10 Hz when accounting for the change in this wave field.
  PubDate: 2015-02-19T01:33:25-08:00
  DOI: 10.1177/0954409713511449
  Issue No: Vol. 229, No. 3 (2015)
Passive suspensions for ride quality improvement of two-axle railway
vehicles
- Authors: Jiang, J. Z; Matamoros-Sanchez, A. Z, Zolotas, A, Goodall, R. M, Smith, M. C.
  Pages: 315 - 329
  Abstract: The aim of this paper is to investigate the possibility of improving the ride quality of a two-axle railway vehicle with a single-stage suspension by means of passive suspensions employing an inerter device. The inerter is a mechanical one-port element that is analogous to a capacitor in electrical circuits. The goal is to improve the ride quality in both the vertical and lateral motions in response to track irregularities. Performance benefits for several simple passive suspension layouts are demonstrated and compared with the conventional scheme. The elastic effects of the damper and inerter device are then taken into consideration for practical purposes. The optimum parameter values of the damper, inerter and the parameters representing the elastic effects provide guidance for mechanical design purposes.
  PubDate: 2015-02-19T01:33:25-08:00
  DOI: 10.1177/0954409713511592
  Issue No: Vol. 229, No. 3 (2015)
Traction, curving and surface damage of rails, Part 2: Rail damage
- Authors: Grassie; S. L.
  Pages: 330 - 339
  Abstract: The tangential forces on a rail resulting from a combination of traction and curving are considered. These forces are a significant component of both wear and shakedown. These two simple mechanisms can be used to understand most types of damage that occur on both rails and wheels.
  PubDate: 2015-02-19T01:33:25-08:00
  DOI: 10.1177/0954409714541648
  Issue No: Vol. 229, No. 3 (2015)