A case study of rail corrugation phenomenon based on the viewpoint of friction-induced oscillation of a wheelset-track system

An interesting rail corrugation phenomenon unreported in open literature is found in Beijing metros, in which the wavelength of rail corrugation in the Cologne egg sleeper section is obviously different from that in the fixed dual short sleeper section, although both sleeper sections are located on an identical sharp curved track. Based on the viewpoint that friction-induced oscillation is the main cause of rail corrugation in some cases, three multiple-wheelset-track models in the transitional section on an identical sharp curved track are built in this paper. The phenomenon is researched by adopting the complex eigenvalue method together with the transient dynamic method. The simulation results are consistent with the corrugation measured in real metros. It can be found that the unstable oscillations mainly occur on the low rail and the relevant frequencies are noticeably different in different sleeper support sections. The dominant unstable oscillation frequencies in the fixed dual short sleeper and Cologne egg sleeper sections are about 201 and 422 Hz, respectively. However, when a sharp curved track is supported only by fixed dual short sleepers or Cologne egg sleepers, the unstable oscillation frequencies are close to each other, which are both about 420 Hz. Therefore, the corresponding wavelengths of rail corrugation are different in different conditions. The local special phenomenon can be satisfactorily explained and the viewpoint of friction-induced oscillation can be further verified.