On short-pitch rail corrugation of suburban express railway caused by localized rail-bending vibrations within the bogie wheelbase

Suburban express railways have developed rapidly in China in recent years. One suburban express line suffered from serious interior noise issues caused by short-pitch rail corrugation. Field investigations show that short-pitch rail corrugation occurred on different track forms. The wavelength of short-pitch rail corrugation on different track forms is almost the same and the dominating wavelengths are 50−63 mm in the 1/3 octave band, corresponding to the passing frequency of 630 Hz in the 1/3 octave band. Field measurements and numerical simulations were carried out to investigate the cause of the corrugation. The results indicate that the localized rail third-order bending vibration within the bogie wheelbase is the root cause of short-pitch rail corrugation. The damping ratio of this mode and the track decay rate are very low, resulting in this mode being easily excited. The rail welding irregularities are the main excitation source of the localized rail third-order bending vibration.