Railway vehicle critical hunting speed (CHS), running safety and ride comfort are factors to be vitally investigated for the study of its dynamic behaviour. In this seminar, a numerical investigation of the nonlinear dynamic behaviour of a railway vehicle running on tracks of
various radii is carried out using a mathematical model of the vehicle-track combined system. Using single and two point contact scenarios, nonlinear CHS and running safety of the vehicle are evaluated. The model consists of a 25-degrees-of-freedom system with four wheel-sets, two truck frames, two bolsters and a carbody. The track is idealized as a laterally flexible springmass-damper system. The model is solved for the dynamic response in the time domain using Runge-Kutta fourthorder method. Limit-cycle-type oscillation is adopted to evaluate the
nonlinear CHS. Furthermore, the influence of material and wheel/rail geometric parameters on vehicle running safety and ride quality are discussed. Running safety is based on derailment quotient and offload factor. Ride quality and comfort is evaluated using sperling ride index and sperling comfort index.