The dynamics equation of the vehicle-track coupling system based on energy principle is a large-scale coupled equation set. Within this system, the vehicle and the track structure are interdependent, coupled through the wheel-rail contact force. This chapter establishes three progressively complex models: (1) a moving element model for a single wheel, (2) a moving element model for a single wheel incorporating a primary suspension system, and (3) a moving element model for a single wheel with both primary and secondary suspension systems. Based on these models, the algorithm for simultaneously solving the dynamic responses of the train and track is described, and the corresponding explicit formulas are presented. As an application example, a dynamic analysis of the train-track-bridge coupling system is conducted, yielding several conclusions. The source code, “Dynamics Calculation Program WTBDYN_1.0 for the Moving Wheelset with Primary and Secondary Suspension-Track-Continuous Bridge Coupling System,” developed using MATLAB mathematical tools, is provided in Appendix D.