Spalling defect of head-hardened rail in railway turnouts

Abstract

This paper investigates the spalling degradation process that could be involved in railway turnouts. By considering the network's failed rails, metallographic examinations revealed the development of subsurface micro-cracks attributed mainly to the non-metallic inclusions. Using Murakami & Yanase equations, the critical size of inclusions leading to the subsurface initiation is discussed in the case of a headhardened rail (350HT) and a standard one (R260). Our findings suggest that the available studies, such as the Kitagawa-Takahashi diagram, overestimate this size on the rail's top surface.