Abstract：In order to study the change of the mechanical behavior of the elastic bars in different transitional sections in the fast-metro system (FMS) , a dynamic model of the transitional section of the metro vehicle-track was established to explore the dynamic based on the theory of vehicle-track coupling dynamics and multi-body dynamics theory displacement of the elastic bars when the metro vehicles was passing quickly three-dimensional solid finite element model of the e-type bar was constructed based on the finite element theory, and the dynamic displacement of the bar was applied to this model as a boundary condition to study the stress variation law of the elastic bar in the rail transit region under the condition of fast running metro, and the control limit of rail displacement difference was put forward on this basis. Results showed that, when the vehicle running through the track transition section at a speed of 120 km/h, the dynamic displacement of elastic bar on the floating slab track side was larger than that of the monolithic roadbed track. The maximum dynamic stress of the elastic bar occurred at the rear arch of it. It was suggested that the rail displacement difference in the transition section of the rapid metro track should be less than 1. 6 mm to ensure the normal use of the elastic bar and the safe operation of the metro train.

Keyword：floating slab track;monolithic roadbed track;transition section;elastic bar;dynamic stress;