Abstract:Research purposes: The rack railway has good climbing ability and has become the main type of mountain railway. In order to study the influence of seamless rack on the continuous welded rail (CWR) on the simply supported girder bridge of the rack railway, a rail (rack)-sleeper-bridge-pier integration model was established based on the bridge-track interaction and the characteristics of rack railway on bridges. The influence law of the seamless rack on the longitudinal force and deformation of the CWR on the bridge and the pier force is obtained.Research conclusions: (1) The seamless rack mainly affects the rail braking force and rail gap compared with the traditional CWR on the bridge. (2) With the increase of the gradient of the railway, the rail longitudinal force, the bridge pier longitudinal force, and the rail gap all decrease under the expansion, deflection and rail breaking conditions, the rail braking force, bridge pier longitudinal force and relative displacement between bridge and rail all increase under the braking condition. (3) When the railway gradient increases to 480‰, the rail expansion force, rack expansion force and abutment force decrease, the expansion force of rail and rack decreases by 4.24%, and the bridge pier abutment force decreases by 4.17%. The rail deflection force, the rack deflection force and the abutment force all decrease, the rail deflection force, the rack deflection force and the abutment longitudinal force decrease by 15.07%, 12.77% and 11.18% respectively. The rail braking force, the rack braking force, the longitudinal force of the bridge pier, the relative displacement of the rail bridge and the relative displacement of the rack bridge increase by 3.12 times, 4.37 times, 3.51 times, 3.33 times and 4.60 times respectively. As for the rack railway, the longitudinal instability should be avoided. The rail gap increases by 3.44%, and the pier abutment force decreases by 4.60%. (4) The research results could provide guidance for the design of CWR on bridges for rack railway.