Influence of different transition zones on the dynamic response of track-subgrade systems

A railway track-subgrade system is modeled using the finite element method (FEM). Two different transition zones between a bridge and an ordinary subgrade, usually used for high speed passenger lines in China, are investigated. Both the calculated vertical displacement and acceleration of the rail and the slab and the calculated vertical displacement and the stress of the subgrade surface of the two transition zones are compared. The dynamic response of the two-part transition section is better than that of the inverted trapezoid transition section, and a 30-m length of both transition sections is recommended. The dynamic response of the track-subgrade system changes abruptly after the first 3 m of the transition section, measured from the bridge abutment. Special attention should be given to this critical zone during construction.