Theoretical calculation of the track mass in the motion of unsprung masses in relation to track dynamic stiffness and damping

Abstract

In order to calculate the load on the track in the position of a sleeper at the time when an isolated axle of the vehicle passes, it is necessary to determine the mass of the railway track that participates in the movement of the unsprung masses of the vehicle. In this paper, the track is modelled as a vibrating string. Its movement is analysed theoretically, and the length that participates and influences the movement of the unsprung masses is calculated. The result of the theoretical calculation is compared to the results of the measurements that have been carried out in a number of countries. The influence of the dynamic stiffness and damping of the track is also investigated.

Keywords:

• unsprung (non-suspended) masses
• dynamic stiffness
• static stiffness
• fastenings
• track mass