Formation Mechanism of 160-250mm Wavelength Rail Corrugation in Steel-Spring Floating Slab Tracks: A Multi-Wheel Standing-Wave Effect

Rail corrugation with wavelengths of 160–250 mm frequently occurs in metro steel-spring floating slab tracks, posing a serious threat to operational safety and ride comfort. In this study, a vehicle–track coupled dynamics model is developed that integrates wheel–rail contact mechanics and wear evolution mechanisms. Time-domain simulations are performed to track the entire corrugation development process from initiation to growth. The results reveal that corrugation arises from resonance coupling between the natural vibration modes of the track structure (72–112 Hz) and the wheel–rail dynamic response. The evolution of corrugation exhibits multi-scale characteristics: at the macroscopic scale, standing waves with a wavelength of 2.2 m appear, corresponding to the vehicle wheelbase; at the microscopic scale, short-pitch waves with a wavelength of 35 mm develop under high-frequency excitation at 512 Hz. Parametric sensitivity analysis shows that fastener stiffness significantly influences corrugation development in the 160–250 mm wavelength range. Increasing the fastener stiffness from 10 MN/m to 60 MN/m effectively suppresses corrugation growth, whereas variations in steel-spring stiffness within the range of 3.3–16.5 MN/m have a negligible effect.