A three-dimensional vehicle-track coupled dynamics model, with the inclusion of the axle-box bearings, has been developed, which considers the coupling effects between the bearing and the vehicle components. Some non-linear factors, such as time-varying bearing stiffness, bearing clearance, wheel-polygonal wear and the non-linear wheel-rail contact forces, are also considered. Dynamic analysis has been implemented through numerical simulations that consider different amplitudes and harmonic orders of measured and idealised polygonal wheel wear. Both model analysis and validation were supported by field tests. Results show that the roller-raceway contact forces increases with vehicle speed and the amplitude of polygonal wear. However, the influence of wear upon the axle-box bearing is found to be small in the low-speed range, but at higher operating speeds, polygonal wear leads to a rapid increase in bearing contact forces and the potential for degradation. During vehicle operations, both high order (17th to 20th order) and lower order (1st to 4th order) wheel-polygonal wear patterns are generated. The former's influence on axle-box bearing forces is more significant. Hence, the identification and rectification of this order of wear should form part of maintenance practice and potentially also be considered in the design of axle-box bearings for high-speed trains.

Summary In order to examine the static and dynamic behavior of the pantograph-catenary system, a special teat facility is established and described in this paper. Since the catenary is difficult to be modeled by a hardware teat facility indoor, a mixed theoretical-experimental technique is introduced, in which the pantograph is an actual one but the catenary is just an input of a mathematical model. Bayed on setting up the hybrid simulation teat device of the pantograph-catenary system, the dynamic behavior of the system under overhead equipment with variant parameters is analyzed for different speed. The effect of the presag and the surface irregularities of contact wire on current-collection has been studied.

This study investigates the effects of polygonal wear of wheels on the dynamic performance of the gearbox housing of high-speed trains. First, a dynamics model of the driving system is developed considering gear meshing and flexible deformation of the gearbox housing. Responses of the gearbox housing are calculated using the modal superposition method. Then, a multibody dynamics model of a railway motor car is established considering the driving system. Rig tests in the laboratory and field experiments on the Beijing–Shanghai high-speed rail line are, respectively, performed. Based on the simulation and experiments, the dynamic characteristics of the gearbox housing of the motor car are analysed. The results of the analysis show that polygonal wear can significantly influence the vibration of the gearbox housing, and the maximum amplitude of the acceleration of vibration is more than 200 g. In addition, resonance of the gearbox housing occurs due to the 20th-order polygonal wear. In the resonance region, the oil level sight glass of the gearbox housing vibrates severely, contributing immensely to its cracking.