ABSTRACT: The article considers the impact interaction of a railway vehicle with a fixed barrier. The movement of the vehicle is carried out at different velocities. A dynamic model of a buffer is offered, which includes an elastic element, a damper, and a friction mechanism. The elastic element has a nonlinear characteristic. The damper is defined by equivalent viscous resistance. The friction mechanism creates a dry friction force. Two phases of interaction are considered. The first phase is to reduce the vehicle velocity to zero. The second phase considers the distancing of the vehicle from the fixed barrier until the moment of separation of the buffer from it. The loss of kinetic energy at different velocities is determined as well as at a variation of the dynamic parameters of the buffer. The results of the study would be useful in developing new buffer constructions for modern light rail vehicles.