Rail corrugation: advances in measurement, understanding and treatment

A review is presented of progress over the last decade in the understanding, measurement and treatment of corrugation. A great diversity of dynamic behaviour causes corrugation. All types of corrugation identified to date are constant frequency rather than constant wavelength phenomena. Where corrugation arises from differential wear, friction modifiers offer broad potential to reduce corrugation, regardless of its detailed cause. It is possible to measure amplitudes of corrugation of a few microns at walking speed, which has made it possible to propose objective standards for rail reprofiling to remove corrugation.