Analysis of Evolution Trends of Rail Corrugation in Slope Sections of Metro Lines

To investigate different rail corrugation phenomena in slope sections of metro lines, a detailed analysis is conducted using field research and numerical calculations. First, referring to the line situation of the measured section, a vehicle–track coupling dynamics model was established. Then, using the numerical model, the wheel–rail contact stick-slip characteristics under different line conditions were calculated and analyzed, and the different formation mechanisms of rail corrugation explained. Finally, the development trends of rail corrugation were analyzed by considering the effect of corrugation on the rail surface. The results show that the outer rail corrugation in the measured section is distributed mainly in the uphill curve section, while the inner rail corrugation is distributed mainly in the downhill curve section, and the corrugation wavelength is 42.25–50.91 mm. Surface defects can contribute to creep saturation of wheel–rail contact, increasing the possibility of stick-slip vibration, which might induce rail corrugation. The outer rail corrugation in the measured section is caused by stick-slip vibration induced by creep saturation of wheel–rail contact under the uphill curve condition. The inner rail corrugation is caused by creep saturation of wheel–rail contact, triggered by wheel–rail surface defects under the downhill curve condition, and the associated stick-slip vibration. Irregularity on the rail surface can exacerbate the level of stick-slip vibration in the wheel–rail system, contributing to continued development of the irregularity, which can culminate in significant rail corrugation.