A Study on Prevention Measures for Gauge Corner Cracking

There have been many reports of wear and rail damage caused by wheel/rail contact on conventional railway lines in Japan. In particular, rail squats have been commonly reported and gauge corner cracking has been frequently observed on curved high rails with a radius of curvature of approximately 800 m. These forms of damage lead to rail breakage as the cracks develop with the repeated passage of railway vehicles. Predicting crack growth and developing countermeasures is therefore essential for establishing management methods. Furthermore, it is important to reduce the rate of occurrence of these cracks because it is difficult to remove the cracks once they occur. As a countermeasure against rail squats, in addition to the development of a rail grinding method to remove fatigue layers and small cracks on the rail surface, bainitic rails have been developed that promote self-removal of fatigue layers and small cracks by accelerating wear development. However, the advancement of gauge corner cracking is more complicated; for example, gauge corner cracking continuously combines with head checks. At present, countermeasures have not been taken in order to suppress the formation of gauge corner cracking, and there is an urgent need to propose an effective method for doing so. In the present study, countermeasures to reduce gauge corner cracking are proposed by changing the cross-sectional profile of the high rail and reducing the wheel/rail contact pressure and the effectiveness of this method is examined. A mathematical model is constructed from the viewpoint of multi-body dynamics, and the wheel/rail contact pressure at the location at which gauge corner cracking occurs is examined.