An Experimental Investigation of Potential Causes for Car-Body Hunting Motion of High-Speed Train

Car-body hunting motion (CHM) has a significant impact on the ride comfort and safety of high-speed trains (HSTs). In this paper, tracking tests of car-body hunting phenomenon occurring on a high-speed train travelling on a Chinese railway line were carried out. In the first stage, the information such as car-body hunting feature and the train running conditions were investigated. The potential causes and key influence factors of this abnormal phenomenon were studied. In the second stage, several countermeasures such as reprofiling wheels (RW), adjusting the height of the car-body supporting point (AHCSP), were put forward. The comparative tests after the adjustment measures were carried out. The test results show that the vehicle sways abnormally during the acceleration stages and high-speed passing station stages. When the CHM appears, the vehicle lateral comfort index is obviously larger than the vertical index, which obviously exceeds the limit value. The main frequency peak of the car-body lateral acceleration appears at 1.22 Hz, which is close to the natural frequency of car-body lower center roll mode. Many frequency doubling components of this frequency appear at the same time. Through the successive implementation of CHM and RW measures, the CHM phenomenon has been greatly improved, the abnormal vibration of the car-body has disappeared, and the train has resumed normal operation.