Complex nature of white etching layer in rails in long-term operation

The purpose of the research is to generalize the knowledge about the nature of white etching layer (WEL) and mechanisms of its formation. Analysis of last foreign researches on WEL was carried out. As a result, a complex nature of WEL was established. The knowledge of main layer's properties, its role and mechanisms of formation were generalized. It was detected that WEL is an initiator of cracks therefore the understanding of its structure and properties is important for avoiding the formation of the structure on rails’ surface thus improving their operational properties.