The train collision dynamic theory is an acceptable method for new vehicle design, which can save a great deal of simulation and experimentation. A train collision dynamic model that considers the longitudinal and vertical coupling is established. The vehicle subsystem and the track subsystem are also considered in the model through the function of the link between the wheel/rail subsystems and the coupler buffer/anti-climber subsystems. The entire train model is analyzed with a coupled feedback system. The dynamic simulation program of the coupled system is developed, the calculation flow of the coupled model is given, and the explicit time domain solution of the model is realized. Two numerical examples with the same kind of vehicle were completed, and the numerical results are compared with the finite element simulation results. The results show that the coupled model is not only close to the finite element model but also greatly shortens the solution time of the collision response. The accuracy and theory of the collision dynamics model in this article are verified. The results of the paper provide new theoretical evidence and a simulation method for further research on the design of the crashworthiness of rail vehicle structures and the collision dynamic evolution during a train collision.