Two-axle Bogie Research Articles

Evaluation of the vertical vibrations behaviour of the bogie at failure of the dampers in the primary suspension of the railway vehicle

The paper aims to evaluate the behaviour of vertical vibrations of a two-axle bogie at failure of a damper in the primary suspension of the vehicle. The level of vibrations in the bogie is shown to rise as a consequence of the imbalance triggered in the system by the fault damper, resulting in dynamic interferences between the bounce and pitch vibrations of the bogie. This fact is highlighted by the results derived from the numerical simulations, which feature the frequency response functions of the bogie during rolling on a track with vertical irregularities. Various scenarios will be considered for lowering the damping constant in comparison with the reference value.

Dynamic Investigation of the Hunting Motion of a Railway Bogie in a Curved Track via Bifurcation Analysis

The main purpose of this paper is to analyze and compare the Hopf bifurcation behavior of a two-axle railway bogie and a dual wheelset in the presence of nonlinearities, which are yaw damping forces in the longitudinal suspension system and heuristic creep model of the wheel-rail contact including dead-zone clearance, while running on a curved track. Two-axle railway bogie and dual wheelset were modeled using 12-DOF and 8-DOF system with considering lateral, vertical, roll, and yaw motions. By utilizing Lyapunov’s indirect method, the critical hunting speeds related to these models are evaluated as track radius changes. Hunting defined as the lateral vibration of the wheelset with a large domain was characterized by a limit cycle-type oscillation behavior. Influence of the curved track radius on the lateral displacement of the leading wheelset was also investigated through 2D bifurcation diagram, which is employed in the design of a stable model. Frequency power spectra at critical speeds, which are related to the subcritical and supercritical bifurcations, were represented by comparing the two-axle bogie and dual wheelset model. The evaluated accuracy to predict the critical hunting speed is higher and the hunting frequency in unstable region is lower compared to the dual wheelset model.

Identification of the Vibration Environment of Railway Infrastructure

The subject matter of vibrations in railway transport is still an ongoing cognitive issue. In terms of an increase of speed, size, as well as weight of rail vehicles, the scale of effects of vibrations generated when a train moves also grows. However, the authors decided to conduct research and analyze vibrations in a different approach. The article presents the results of the research which aim was to identify the vibration environment of the railway infrastructure. In order to do this, the research on a test track equipped with typical devices of the railway infrastructure, such as crossing signaling devices, point machines was conducted. Additionally, certain experiments were conducted in the environment of other railway occurrences as result of which vibrations are generated. Experiments of a vehicle passage through a level crossing were performed and a passage of a light rail vehicle in a form of a two-axle bogie was simulated. This research aims at analyzing the forms and distributions of vibrations in respect of a possibility to separate signals in the actual environment in which they occur and where often several forced vibrations overlap.

Control of the traction electric drive of a hybrid shunting locomotive with asynchronous motors in the realization of critical forces

The peculiarities of the structure and regulation of an electric traction drive of the TEM9H prototype four-axle hybrid shunting locomotive, which has two-axle bogies and is connected in parallel asynchronous traction motors to one inverter, are considered. Using very dynamic algorithms for a discontinuous control of asynchronous motors in the regulation of the flux linkage of the stator and the electric battery with a large energy level and superconductors allows one to do without free diesel power for traction to adjust the force of traction required by law, applying the new algorithms of the maximum tractive and braking efforts. The pilot locomotive does not include inclined rods or special loaders to balance the vertical load of the axles of the locomotive, whereby the difference in vertical loads between the bogies of the locomotive is about 6 t at the nominal electromagnetic torque of the motor. Promising control algorithms of a traction electric drive of the TEM9H hybrid shunting locomotive with the joint regulation of asynchronous motors, allowing us to compensate for deficiencies in the design of the running gears and to ensure that the potential of adhesion is not less than 90% in a mode with maximum exertion, are analyzed on the basis of computer simulation.

Vertical vibrations of composite bridge/track structure/high-speed train systems. Part 2: Physical and mathematical modelling

A theory of one-dimensional physical and mathematical modelling of the composite (steel-concrete) bridge/track structure/highspeed train system is developed including viscoelastic suspensions of rail-vehicles with two two-axle bogies each, non-linear Hertz contact stiffness and one-sided contact between wheel sets and rails, the viscoelastic and inertia features of the bridge, the viscoelastic track structure on and beyond the bridge, approach slabs, and random vertical track irregularities. Compared to the state-of-the-art, the physical model developed in the study accurately reproduces dynamic processes in the considered system. Division of the system into the natural subsystems, a method of formulation of the equations of motion partly in implicit form and the finite element method are applied. Vibrations in the vertical plane of symmetry are described by more than nine matrix equations of motion with constant coefficients. Couplings and non-linearity are hidden in the generalized load vectors. The equations of motion are integrated using the implicit Newmark average acceleration method with linear extrapolation of the interactions between the subsystems.

Vibrations of Bridge / Track Structure / High-speed Train System with Vertical Irregularities of the Railway Track

The study presents the vibration theory and random dynamic analysis of the series-of-types (designed by the author) of composite (steel-concrete) bridges loaded by a German ICE-3 high-speed train. The vibration theory includes: a continuously welded ballasted track structure, viscoelastic suspensions of rail-vehicles with two two-axle bogies each, non-linear Hertz contact stiffness and one-sided contact between the wheel sets and the rails, the viscoelastic and inertia features of the bridge, the viscoelastic track structure on and beyond the bridge, approach slabs. The basic random factor, i.e. vertical track irregularities of the track, is taken into consideration.

Effect of random track irregularities on selected composite bridge / track structure / high-speed train system vibrations

A theory of the quasi-exact physical and mathematical modelling of the composite (steel–concrete) bridge / ballasted track structure / high-speed train system (BTT) was developed, including viscoelastic suspensions of rail-vehicles on two-axle bogies, the non-linear Hertz contact stiffness and one-sided contact between the wheel sets and the rails, the viscoelastic and inertia features of the bridge, the viscoelastic track structure on and beyond the bridge, the approach slabs, and random track irregularities. Based on this theory, advanced computer algorithms for the BTT numerical modelling were written and a computer program to simulate the vertical vibrations of the BTT systems was developed. The bridge subject to the preliminary dynamic analysis and designed according to Polish standards has a 15.00 m span length. The bridge was loaded by the German ICE-3 high-speed train moving at the critical (180 and 270 km/h) and the maximum (300 km/h) operating speeds.

Bifurcation analysis in hunting dynamical behavior in a railway bogie: Using novel exact equivalent functions for discontinuous nonlinearities

This paper presents an investigation on bifurcation of railway bogie behavior in the presence of nonlinearities which are yaw damping forces in longitudinal suspension system and the friction creepage model of the wheel/rail contact including clearance. Through Routh–Hurwitz stability criterion and a more accurate model than Yang and Ahmadian, the analytical expression of critical speed is achieved as well as the limit cycle frequency. Then, by Averaging method and analytical critical speed, the amplitude of the limit cycle is determined while the wheel/rail clearance is taken into account. To solve the nonlinear equations analytically, both dead zone discontinuity and yaw dampers must be formulated properly. In this direction, a suitable and novel exact equivalent functions (EF) is introduced. Furthermore, 2D and 3D bifurcation diagrams are depicted to show the mechanism creation of Hopf bifurcation which is employed in the design of stable wheelset systems. Finally, the accuracy of one-axle model results for the prediction of critical speed is evaluated in contrast with two-axle bogie model.

Estimation of Applied Forces on Railway Vehicle Wheelsets from Measured Vehicle Responses

In this paper, a finite element (FE) model of a railway freight vehicle is proposed to be used in the identification of applied forces to the wheelsets. The proposed model is comprised of two, two-axle bogies of type H665 and a freight wagon. The model is updated in two stages. First, the bogie is updated by using modal data extracted from measurements on an actual bogie separated from wagon. Secondly, the whole structure of the vehicle is updated by modal data obtained from a test conducted on the vehicle in the laboratory. Since the proposed model is relatively large, it is reduced to some desirable points through the superelement analysis method, in order to reduce the cost of computation. The final reduced model is then used to identify the applied forces resulted from irregularities of track.

360545 ANALYTICAL STUDY OF THE MECHANISM OF WHEEL LOAD VARIATION ON A TWO-AXLE BOGIE(Safety,Technical Session)

The purpose of this study is to investigate the mechanism of wheel load variation of a high-speed train running on rail track with short-wavelength irregularity effecting on the running safety. In order to investigate the mechanism, the numerical simulation is conducted. The simulation model consists of the two-axle bogie and the track. The track consists of rail, rail pad, sleeper, ballast. The rail is expressed as the flexible beam described using the Absolute Nodal Coordinate Formulation in order to obtain the rail deformation more precisely. As a result of this study, we obtained further the information of the wheel load variation while two wheels passing on the rail with irregularity. That is, the wheel load variation rate of two-axle bogie model at 270km/h becomes larger in the case of the irregularity wavelength 1.1-1.2m as well as one-axle bogie model. However, the difference between the leading wheel and the trailing wheel occurs in terms of the magnitude. And the magnitude relation between the leading wheel and the trailing wheel changes according to the wavelength with the irregularity. We discuss the mechanism of these phenomenon obtained by the simulation.

A model-less technique for the fault detection of rail vehicle suspensions

This paper presents a novel method for the fault detection and condition monitoring of rail vehicle suspensions. The proposed technique takes advantage of the vehicle (suspension) configurations that are often symmetrical, and explores the additional dynamic interactions between different motions of a bogie or body caused by the failure of suspension components. The basic principle of the proposed detection method is presented and the interactions due to suspension fault conditions are analysed using a conventional two-axle bogie. Side-view models of a bogie vehicle are used in the study to demonstrate the effectiveness of the novel method in detecting damper faults in the suspensions. Both linear and bi-linear dampers are studied.

Effect of sleeper pitch on rail corrugation at a tangent track in vehicle hunting

The effect of sleeper pitch on the initiation and development of rail corrugation at tangent track is investigated using a numerical method in vehicle hunting. The numerical analysis considers a combination of Kalker's rolling contact theory with non-Hertzian form, linear frictional work model and the dynamics model of a half railway vehicle coupled with a tangent track. Kalker's theory is modified. The half vehicle has a two-axle bogie and doubled suspension systems. It is treated as a full dynamic rigid multi-body model. In the tangent track model, an Euler beam is used to model each rail, and the backward moving discrete supports of the rails are considered to simulate the action of the discrete sleeper supports on the wheels/rails in rolling contact, when the train running on the track. The sleepers are treated as rigid bodies and the ballast bed is replaced with equivalent mass bodies. The effect of the discrete sleeper supports on the normal loads of the wheels/rails is analyzed at different speeds. The easily excited resonant frequencies of the wheelset and the track at different speeds are investigated in detail. In order to find the conditions necessary for rail corrugation occurring at the tangent track through numerical simulation, the vehicle hunting at higher speed is caused by setting the appropriate initial displacement condition of the vehicle system. The numerical results show that when the yaw angle of the wheelset reaches its maximum value in the vehicle hunting the lateral creepage of the wheel and rail oscillates at sleeper passing frequency and higher track frequencies. Therefore, rail corrugation due to wear initiates with several frequencies including sleeper passing frequency, and grouped near the peaks of the wheelset yaw angle. With increasing passage number of the vehicle in hunting, the corrugation became serious and also extended further along the rail.

Effect of discrete track support by sleepers on rail corrugation at a curved track

The paper investigates into the effect of discrete track support by sleepers on the initiation and development of rail corrugation at a curved track when a railway vehicle passes through using a numerical method. The numerical method considers a combination of Kalker's rolling contact theory with non-Hertzian form, a linear frictional work model and a dynamics model of a half railway vehicle coupled with the curved track. The half-vehicle has a two-axle bogie and doubled suspension systems. It is treated as a full dynamic rigid multi-body model. In the track model, an Euler beam is used to model the rail, and the discrete track support by sleepers moving backward with respect to the vehicle running direction is considered to simulate the effect of the discrete sleeper support on the wheels/rails in rolling contact when the vehicle moves on the track. The sleeper is treated as a rigid body and the ballast bed is replaced with equivalent mass bodies. The numerical analysis exams in detail the variations of wheel/rail normal loads, the creepages, and the rail wear volume along the curved track. Their variations are much concerned with the discrete track support. The numerical results show that the discrete track support causes the fluctuating of the normal loads and creepages at a few frequencies. These frequencies comprise the passing frequency of the sleepers and the excited track resonant frequencies, which are higher than the sleeper passing frequency. Consequently, rail corrugation with several wavelengths initiates and develops. Also the results show that the contact vibrating between the curved rails and the four wheels of the same bogie has different frequencies. In this way, the different key frequencies to be excited play an important role in the initiation and development of curved rail corrugation. Therefore, the corrugations caused by the four wheels of the same bogie present different wavelengths. The paper shows and discusses the depths of the initial corrugations caused by the four wheels of the same bogie, at the entering transition curve, the circle curve and the exit transition curve of the curved track, respectively.

Tractive effort, curving and surface damage of rails: Part 1. Forces exerted on the rails

Traction and curving are the principal causes of high tangential forces between railway rails and wheels. The magnitude and direction of these forces are calculated for equilibrium curving of a conventional two-axle bogie in curves of 600–1800 m radius, both without traction and for a level of tractive effort of 0.28 times the normal load of the vehicle. For a non-powered bogie, the tangential force is greatest at the high wheel of the leading axle and least at the high wheel of the trailing axle. At high traction levels, the tangential force is high at both leading and trailing high rail wheels. The ability of a bogie to steer deteriorates as tractive effort increases. Whereas a low inter-axle yaw stiffness helps a non-powered bogie to steer better, steering of a bogie with low yaw stiffness is poorer under traction. Cant deficiency both redistributes tangential loads between the four wheels of a bogie in a desirable way and reduces the maximum of the four loads for all levels of applied traction.

Active Steering of a Rail Vehicle with Two-Axle Bogies Based on Wheelset Motion

Summary This paper deals with a basic study on the actively steered rail vehicle with two-axle bogie trucks, which employs a control law based on the self-steering ability of wheelset. However, this control law not only helps the steering performance, but also tends to lower the running stability. Two methods are proposed to improve the stability. The first method is to add a feedback of wheelset lateral velocity, the second one is to give some time lag to the control force, and both are proved to be affective. Here, the latter is more practical method and the delay of control due to the time lag does not deteriorate the steering performance.

Nonlinear hunting stability analysis of high-speed railway vehicles on curved tracks

Based on the heuristic nonlinear creep model, the coupled nonlinear differential equations for the motion of a two-axle bogie moving on curved tracks are derived, considering the inertia forces. To illustrate the accuracy of the analysis, the limiting case is examined. Finally, the difference between the influences of the suspension parameters on the critical hunting speed evaluated by the linear creep model and the nonlinear creep model is compared. In addition, the influences of the suspension parameters on the critical hunting speed with various radius of curvature are also presented.

A302 Effect of Gauge Widening on Curve Negotiation of Two-Axle Bogie Vehicles Considering Steering Mechanism and Wheel Tread Profile

According to the decrease of the three-axle bogie for locomotives in Japan, the need for diminution of the gauge widening in curved track has been pointed out by rail maintenance division. Meanwhile, bolsterless bogies which can have more steering ability are employed in many rail vehicles, and wheels with profiled tread have been used widely. For vehicles which have such bogies and wheels, it is expected that the gauge widening still keeps its effect on the curve negotiation even now. In this paper, the curving performance under the presence of gauge widening is investigated in detail considering the recent trend. The wheel lateral forces during curve negotiation obtained by numerical simulation are compared among vehicle types classified with truck mechanisms and wheel tread shapes. As a result, it is shown that the effectiveness of gauge widening exists for bolsterless truck and steering truck, but the availability to the trucks with profiled wheel is little because the change of wheel shape, from conical tread to profiled one, gives much effect on the performance. Then, a modification of shape in profiled tread is examined to get further availability of gauge widening.

Running stability simulation and field testing of two-axle bogie design

Running stability, which limits the maximum safe operating speed of the EMU (Electrical Multiple Unit), largely relies on longitudinal suspension stiffness. However, the longitudinal suspension impairs the steering ability of the rigid railway wheel-sets having conical or profiled-wheel treads on curved track. This limitation is felt particularly in EMUs designed for high operating speeds. This study utilises the multi-body program MEDYNA to explore the running stability of a two-axle bogie design through simulation. Considered herein are the relation of critical speed and conicity, also the damping ratio through 2D and 3D analyses. Field test results are examined to find the lateral displacement of the wheel and the bogie swing angle in order to determine running stability. Hence, the design prediction and field test confirmation of running stability behaviour are studied to further understand one of the most fundamental factors to be considered in the design and engineering development of a bogie.

Theoretical Comparison Between Different Configurations of Radial and Conventional Bogies

This article compares the dynamic behaviour of different configurations of radial and conventional two-axle bogies. In general, the design parameters for a better curve negotiation are not compatible with those for good stability. As the main target of this article is to compare the curving performances of different bogies under the same design basis, several bogie configurations with the same level of stability, obtained by choosing proper primary suspension stiffnesses, have been used. The comparison includes a conventional bogie and three radial bogies with differing self-steering and forced-steering principles in three different passenger services: High Speed, Regional and Mass Transit. The analysis has been concentrated on parameters such as stability, lateral wheel-track forces in curve and wheel wear indices. The results show that the radial bogie configurations studied do not make significant contributions in general applications with regard to a conventional bogie. It is only under specific running conditions and types of service that some radial bogie configurations provide advantages with respect to the conventional bogie.

An Analysis of Curve Negotiation for Two-Axle Bogie Vehicle Considering the Effect of Gauge Widening.

According to the decrease of the three-axle bogie for locomotives, the need for diminution of the gauge widening in curved track has been pointed out by rail maintenance division. Meanwhile, bolsterless bogies which have no side bearer are employed in many railway vehicles recently, and it is expected that various steering bogies will be employed in the near future. For vehicles which have these bogies, the gauge widening keeps its effect on curve negotiation even now. In this study, the dynamical analysis is carried out about the relationship between the gauge widening and the track load, considering the bogie mechanism. Numerical simulation is used for the analysis, and the effectiveness of gauge widening is summarized from dynamical viewpoint of two-axle bogie vehicles. Further, wear indices are introduced, and the wear tendency of flange and tread is estimated quantitatively.