Abstract: As for a fastening system of railway, a vertical dynamic model is established and the formulas of rail vertical forces are deduced in this paper by considering the elastic characteristic of the spring rods and rail pads, and taking the preload force into account as well. Then the characteristic of vertical vibration is analyzed on the basis of the theory of vehicle-track coupled dynamics. Results show that both the preload force and the wheel/rail interaction dynamic force have much effect on the elastic deformation of the spring rods and rail pads. The forces acted on the rail by the spring rods, being the same as the forces by the rail pads, have two parts of forces, such as the preload force and the wheel/rail interaction dynamic force. Thusly it is necessary to separately take the spring rods and rail pads into account in the process of analyzing and designing dynamic performance of the fastening system of railway.