Mechanism analysis of low-frequency swaying motion of high-speed trains induced by aerodynamic loads

Abnormal carbody vibrations can significantly affect the safety and stability of high-speed trains. In this study, we conducted field measurements to analyze low-frequency swaying of a high-speed train on the Chinese alpine railway line. The test results reveal that the tail vehicle of the train swayed laterally in certain sections of the track, resulting in vehicle lateral stability index exceeding the limit. The swaying frequency of the carbody was mainly distributed in the range of 1.4-1.5 Hz. The causes of abnormal swaying were analyzed by establishing a computational fluid calculation model. Computational fluid dynamics calculations revealed that lift force, side force, and yaw moment were higher for the tail vehicle compared to the head and middle vehicles. The train-track coupled dynamics simulation results demonstrate that aerodynamics disturbances may be the key factor to intensify the abnormal swaying of the high-speed train tail vehicle.