Wear and damage behaviors of wheel-rail with different material matchings under various sand deposition densities of rail top in desert environments

In desert environments, the phenomenon of sand particles depositing on the rail top and contaminating the wheel-rail interface is common because the railway is an open system. This work aimed to investigate the wear and damage behaviors of wheel-rail with different material matchings under various sand deposition densities of rail top in desert environments. The results showed that as sand deposition density increased, adhesion coefficient first decreased sharply and then increased slowly, and finally decreased slowly. It was caused by the combined effect of sand solid lubrication, oxide solid lubrication, and surface roughness of wheel and rail. The oxidative wear increased first, peaking at about 0.2 g/m 2 , and then decreased, whereas the fatigue wear decreased consistently. For wheel and rail materials with similar hardness, the wheel-rail material matching with high carbon content exhibited excellent anti-wear and anti-fatigue performances. The wear and damage of wheel and rail were relatively mild when the sand deposition density was lower than 0.4 g/m 2 . • Adhesion transition mechanism as sand deposition density increased was proposed. • Oxidative wear rose first and then declined as sand deposition density increased. • Top layer microstructure of worn surface for different wheel steels were similar. • Wheel and rail steels with higher carbon content had better service performance. • Wear and damage were mild as sand deposition density was less than 0.4 g/m 2 .