A linear model to explain short pitch corrugation on rails

In the present paper a linear model to predict the corrugation formation on railway rails is described. A feedback process between the structural dynamics of wheelset and track, coupled by the contact mechanics, interacting with a wear mechanism, is proposed to explain the features of short pitch corrugation on rails. The wheelset and brake discs are modelled using the finite-element method with solid-types elements. For the track, the discretely supported model developed by Gry is used. This model, based on wave propagation, combines the finite-element method for describing accurately the rail section and periodic structures analysis to consider the support. In this model, rail section strains are allowed. The track and wheelset dynamics are introduced into the global model by using receptances. The forces’ variations at the wheel–rail contact are assumed small compared with the quasi-static forces and creepages, which are obtained through a theoretical model for bogie curving. A transfer function between the initial wheel and rail roughness and the wear spectra in the contact patch is presented. Finally, the study uses the model described above to explain a specific kind of short pitch corrugation that had shown up on low rail in sharp bends on certain section of railway in the Bilbao area. Antiresonances in the vertical structural dynamics together with high values in the lateral dynamics were identified as the main corrugation formation mechanism.