Analysis Method of Formation Mechanisms of Rail Corrugations on Metro Lines

To investigate generation causes of rail corrugation on metro lines, a new analysis method applicable to explain the formation mechanism of rail corrugation is proposed from micro creepage saturation and macro structural stability. The critical value of creepage saturation calculated by the micro determination program for creepage saturation of the wheel–rail system using dynamic methods can be used as the basis for judging the creepage saturation of the wheel–rail system, and when the composite creepage is greater than the critical value of creepage saturation, the wheel–rail creepage reaches saturation. The macro determination program for the structural stability of the wheel–rail system uses a complex modal method to judge the degree of system stability, which can consider the frequency domain characteristics of the system structure with material damping, so it is closer to the actual situation. The numerical results of creep characteristics of the wheel–rail system show that the occurrence section of initial corrugation is consistent with the actual situation of rail corrugation. The numerical results of the structural stability of the wheel–rail system show that frequencies and locations of unstable vibration modes are consistent with the measured rail corrugation. It can be concluded that it is feasible using the proposed analysis method to predict the formation of corrugations. Combining the micro and macro determination programs, it can be concluded that the formation mechanism of the measured corrugation is that under the micro creepage saturation condition, the structural instability vibration at the specific frequency of the wheel–rail system causes rail corrugation.