moving loads;  rail systems;  spectral analysis;  dynamic response;  Discrete wavenumber method

Taking the orbital system under moving load as the research object, the method of track-sleeper-gravel cushion synergy analysis was adopted to simplify the rail system into an elastic foundation beam model, and its dynamic characteristics were analyzed through the calculation of response spectrum and dynamic response. The results show that the critical speed when considering synergy is significantly lower than when not considering synergy, and the critical speed decreases with the increase of the initial frequency. The maximum response of the track always occurs at the observation point (t=0) when the train is running, and it increases with the increase of soil thickness.