Abstract: In order to exactly describe the motion regularity of rolling freight cars at the rear of marshalling yard, and provides a basis for scientifically and rationally planning the installation of anti-rolling devices. The various longitudinal forces existing in the rolling course of train set are analyzed based on the longitudinal dynamics of train. The object-oriented modularization design method is used to develop simulation software for rolling freight cars at the rear of marshaling yard, in which real-time simulation of rolling freight cars in various operating conditions is realized..