Combined friction induced oscillations of wheelset and track during the curving of metros and their influence on corrugation

Abstract

Curving of rail vehicles is often connected with vibrations, which can be caused by rail corrugation or friction induced oscillation in the wheel/rail-contact. This paper deals with heavy vibrations at the running gear of a metro vehicle with a typical frequency of 80 Hz on curves with a radius between 50 and 200 m. Specific characteristics of the vibrations are the occurrence by passing over rails without an initial corrugation and the disappearance if the rails are wet. In the curves of the concerned network, corrugation can also be found with a corresponding wavelength on the outer rails, but the inner rails show shorter wavelengths. For a better understanding of the originating process a simulation model is set up using the commercial Multi-Body-Simulation-Software SIMPACK. The model includes the vehicle and the track. After an identification of the undetermined parameters the model shows the same behaviour as the real system. The vibration is characterized by large amplitudes of the normal force in the wheel/rail-contact. The originating mechanism and the determining parameters of the oscillation are identified. Using a simple wear law the possibility of rail corrugation originated by these vibrations can be shown with different wavelengths on the inner and outer rail as observed in the measurements.