Dynamic response of a train–bridge system under collision loads and running safety evaluation of high-speed trains

• A dynamic model is established for train–bridge system subjected to collision-load.
• Collision greatly enlarges displacement and acceleration responses of bridge.
• Running safety of high-speed train is affected by collision-excited bridge vibration.
• Evaluation method for running safety of high-speed train on bridge to collision.

Based on the authors’ previous work, an extended study of the train–bridge system under collision loads is presented. A continuous bridge with box girders is considered as a case study. The dynamic responses of the bridge and the running safety indices of the train on the bridge under three types of collision loads are analyzed. Large responses of the bridge induced by collision strongly threaten the running safety of trains. An assessment procedure is proposed for the running safety of high-speed trains on bridges subjected to collision loads, and related threshold curves for train speed versus collision intensity are defined.