## 1 Introduction
[10] considered the excitation effects of track irregularity and earthquake action on the train-bridge dynamic interaction system. The dynamic response of each subsystem of the vehicle and bridge was obtained, and the vibration mechanism was analyzed. [PERSON] et al. [11] developed a finite element model to study train-bridge interaction in a high-speed railway context. They focused on a simply supported beam bridge with CRTS II plate and CRH2C high-speed train as the subjects of their research. [PERSON] et al. [12] and [PERSON] et al. [13] took into account the randomness of earthquakes and track irregularity and evaluated the dynamic index of trains during and after earthquakes from a probabilistic perspective. [PERSON] et al. [14] considered seismic residual deformations and studied the influence of additional lateral irregularities of the rail caused by the lateral defection of the girder and train speed on train safety and stability. [PERSON] et al. [15], [PERSON] et al. [16], [PERSON] et al. [17], [PERSON] et al. [18], [PERSON] et al. [19], and [PERSON] et al. [20] studied the effects of the seismic wave incidence angle, seismic wave propagation velocity, seismic intensity, and train speed on the train-bridge dynamic interaction. [PERSON] et al. [21] and [PERSON] [22] investigated the influence of spatial variation on the dynamic performance of a train passing through a bridge and pointed out that the wave passage effect and incoherence effect should not be disregarded in this context, and the tri-directional spatially correlated ground motions may underestimate the random response and running safety. [PERSON] et al. [23; 24] examined the impact of topographic effects on the seismic response of train-bridge systems and found that topography and the incident angle of seismic waves have a significant influence on the system's seismic response. [PERSON] et al. [25; 26], [PERSON] et al. [27], and [PERSON] et al. [28] investigated the dynamic response of train-track-bridge coupling systems under the influence of pulse parameters from near-fault pulse-type earthquakes. The analysis revealed that the dynamic response of the train group is approximately linear and positively correlated with the amplitude of the velocity pulse, and the dynamic response of the train group is negatively correlated with the velocity pulse period. [PERSON] [29] assessed the safe running speed limit under different seismic levels based on the wheel-rail dynamic indicators of CRH3 high-speed train and CRTS III ballastless track deformation indicators. In this study, a train-bridge coupling model was developed to capture the intricate nonlinear behavior between the wheel and rail using ANSYS/LS-DYNA [30]. To investigate the train-bridge dynamic behavior under the influence of earthquakes, we have adopted the CRH2 high-speed train and a high-speed railway double-track steel truss suspension bridge (HSRDTSTSB) across strike-slip fault ground motions (ASSFGMs). To generate the ASSFGMs, an artificial synthetic method, which considers both the fling-step effect with a single pulse and the directivity effect with multiple pulses, was employed. The effects of FCAs and PGRDs were systematically investigated. This paper specifically concentrates on the nonlinear seismic response of the train-bridge system under the combined influence of both train load and seismic load rather than considering the train load in isolation. As a result, the impact of variations in train speed is not discussed in this study due to space constraints.