Mechanism of short pitch rail corrugation: initial excitation and frequency selection for consistent initiation and growth

This paper proposes a new hypothesis for the formation process of short pitch rail corrugation. An FE wheel-track dynamic model is utilized to verify by reproducing corrugation initiation and consistent growth. It found longitudinal compression modes are responsible with necessary initial excitation that allows flexibility vibration. Consistency between vertical bending eigenfrequencies system required growth, which also determines maximum amplitude. Corrugation initiates frequency selection instead wavelength fixing. The proposed mechanism can explain field observations including periodicity in Netherlands, why forms on continuously-supported tracks where pinned-pinned resonance does not exist, small variation train speed.