Rail corrugation occurs frequently in the overlapping section of horizontal-vertical curves in mountain city metro.Rail grind is a commonly used means to restrain the development of rail corrugation,and it is crucial to determine the grinding limit of rail corrugation in rail grind.The vehicle-track system dynamic model in the overlapping section of the horizontal-vertical curves was established based on the field investigation.The influences of rail corrugation characteristics on wheel-rail dynamic response were studied by dynamic analysis.The safety limit of rail corrugation was proposed from the perspective of vehicle operation safety.The finite element model of wheel-rail system in typical rail corrugation section with 50 mm wavelength was established.The characteristics of wheel-rail friction coupled vibration were studied by instantaneous dynamic analysis.The grinding limit of rail corrugation was proposed from the perspective of the development of rail corrugation.It is found from the dynamic analysis results that when the wave grinding wavelengths are 30 mm,40 mm,50 mm,60 mm and 70 mm,the safety limits of rail corrugation depth in the overlapping section of horizontal-vertical curves are 0.03 mm,0.04 mm,0.05 mm,0.08 mm and 0.15 mm,respectively.According to the analysis result of wheel-rail friction coupled vibration,it is found that the wheel-rail system friction coupled vibration increases with the increase of rail corrugation depth.The wheel-rail friction coupled vibration can be suppressed by controlling the grinding limit of rail corrugation depth below 0.02 mm,which can delay the development of rail corrugation.