This investigation demonstrates the wheel wear evolution and related vehicle dynamics of high-speed trains with an operating distance (OD) of around two million kilometres. A long-term experimental test lasting two years was conducted to record the wheel profiles and structural vibrations of various trainsets. The wheel wear, namely the profile shape, worn distribution and wheelset conicity, is investigated for several continuous reprofiling cycles. Typical results are illustrated for the stability analysis, and the ride quality is examined with increasing OD. In addition, the vibration transition characteristics between suspensions are investigated in both the time and frequency domains. The experiments show that the dominant wear concentrates on the nominal rolling radius, and the wear rate increases with OD because of the surface softening resulting from the loss of wheel material. The vibration of structural components is aggravated by the increase of the equivalent conicity of the wheelset, which rises approximately linearly with the wheel wear and OD. High-frequency vibrations arise in the bogie and car body related to the track arrangement and wheel out-of-roundness, causing the ride comfort to worsen significantly. Additionally, the system vibration characteristics are strongly dependent on the atmospheric temperature. Summaries and conclusions are obtained regarding the wheel wear and related vehicle dynamics of high-speed trains over long operating times and distances.

A nonlinear dynamic model for a rubber spring is created and subsequently used to describe the mechanical behavior of rubber mounts in the suspension system of a railroad vehicle. The characteristics of dynamic stiffness and damping relative to the applied displacement amplitude and frequency are investigated both through simulations and measurements. The model is one dimensional and is based on a superposition of elastic force, frictional force and fractional derivative viscous force. The amplitude dependence is represented by a nonlinear frictional component and a fractional derivative calculus approach is used to account for its frequency dependence. The fractional calculus approach considers previous responses in the current calculation, which results in the memory characteristics of rubber being considered. A linear elastic spring component is still needed to describe its static behavior. The least-squares technique is used to obtain model parameters from measurements, and an overall good agreement between the simulations and measurements is obtained. The model only has five parameters and represents a reasonable compromise between accuracy and computational effort, and thus, it is a suitable tool for railroad vehicle dynamics analysis and simulation.