Abstract: Aiming at the problem about simulation and detection of steel rail nuclear injury, a multi-body dynamic model of the vehicle/track was built based on the SIMPACK software, and the elastic steel rail nuclear injury was modeled and integrated by using ANSYS software and FEMBS interface, thus the computer simulation of vehicle axle box vibration response under the different nuclear injury cases was implemented. Then the empirical wavelet transform(EWT) method was introduced to analyze the axle box vibration signal, and the marginal spectrum was employed to identify the characteristic frequency of nuclear injury. Finally, the simulation of different speed and nuclear injury cases was conducted. The simulation results showed that the model could implement the computer simulation of steel rail nuclear injury. The"W" type of vibration amplitude got by EWT of the axle box vibration signal and marginal spectrum analysis could characterize the size and frequency of steel rail nuclear injury, verify the feasibility of steel rail nuclear injury simulation analysis.