Abstract:The influence of track irregularity on vehicle body vibration was investigated to evaluate the vibration situation of vehicle body and analyze the stability level. A mechanical model for vertical vehicle body vibration was established to introduce motive differential equations. The track power spectrum in vertical space domain was transferred into the spectrum in timefrequency domain to establish 3D model of vehicle body by Pro/E software and wheelrail model by SIMPACK. The train simulation model was also introduced by SIMPACK. The vertical vibration response of the vehicle body was calcuated with height irregularity as excitation function. Based on the vehicle response, the stability level of travelling vehicle was evaluated in time domain, and the composition of vehicle vibration acceleration power spectral density was analyzed in frequency domain. Referred Chinese standard of train stability, the performance grade of train stability and vibration were proposed.