A Non-Linear Wheelset Model to Predict Derailment

Abstract The performance of a rail vehicle is a direct function of the ability of its wheelsets to negotiate the track. This paper presents the results from a detailed dynamic simulation study of wheelset motions with special emphasis on safety-related behavior. The wheelset is assumed to maintain continuous wheel-rail contact as it traverses smooth track that may be tangent or curved, and rigid or flexible. The model accounts for nonlinearities due to wheel-rail profile geometry and friction (creep) force and the longitudinal translation of the contact patch as a function of wheelset yaw angle. The results demonstrate non-linear features, such as limit cycles, and extremes of behavior including wheel-lift, and wheel-climb. The model has also been exercised to generate steady-state force and moment characteristics.