Theoretical study of long elastic sleeper track to reduce vibrations induced by subway trains

Long elastic sleeper track (LEST) is a medium vibration reduction track, which is gradually used in urban rail transit in recent years. In order to analyze the structure of LEST used in subways and to study the dynamic effect of the elastic cushion stiffness and vehicle speed, a dynamic model of the vehicle–track–tunnel–soil coupling system was established based on the finite element method and vehicle–track interaction dynamics theory. The results show the following: (1) LEST is more advantageous in vibration reduction performance compared with the common slab track and the low vibration track under the same track stiffness, and LEST also has better integrity and stability than the low vibration track; (2) The lower the cushion stiffness is, the smaller the accelerations of the tunnel wall are, but the dynamic displacements of the track rise in time domain. Considering the dynamic displacements and accelerations, the cushion stiffness is recommended to be 20–30 kN/mm. (3) High vehicle speed has a detrimental effect on the dynamic response, especially the accelerations of track. It is necessary to pay more attention to vibration when the vehicle speed exceeds 100 km/h in the subway if LEST is used.