Rail Corrugation Growth on Curves

Licentiate thesis, 2009

Short-pitch rail corrugation that may develop on the low (inner) rail on small radius curves causes increased noise and vibration levels on railway networks worldwide. In lack of a generally applicable treatment, track authorities are forced to run expensive rail grinding programs on a regular basis to manage these problems. This thesis presents the first stages in the development of a simulation model for the prediction of rail corrugation growth on small radius curves. By gaining a deeper understanding of the complex dynamic wheel–rail interaction phenomena that lead to corrugation growth, preventive actions may be assessed and implemented. In two separate studies, wear modelling and simulation of dynamic vehicle–track interaction have been considered. A method for the calibration of a wear model using measurement data from a wheel–rail test rig is demonstrated. In terms of worn-off area and profile shape, good quantitative agreement between measured and predicted rail profiles is shown. A time-domain model for the simulation of dynamic interaction between a vehicle and a curved railway track is presented. The simulation model is able to simultaneously capture the low-frequency vehicle dynamics due to curving and the high-frequency track dynamics due to excitation by for example short-pitch corrugation on the low rail. The functionality of the model is demonstrated in several numerical examples. A significant influence of the track and wheelset structural flexibilities on the normal and tangential wheel–rail contact forces is concluded. For a track taken as rigid, the proposed model is validated versus a commercial software. To collect data for later use in the validation of the rail corrugation growth prediction tool, a measurement campaign has been performed. The development of corrugation on a 120 m radius curve on the Stockholm metro was monitored by repeated measurements of rail roughness and train pass-by noise. Within a rail grinding interval of one year, severe short-pitch corrugation was generated on the low rail of the curve with maximum peak-to-peak magnitudes of about 0.15 mm.