A laboratory demonstration of rail grinding and analysis of running roughness and wear

Rail grinding has been widely used for rail maintenance to keep the performance of the rail track at satisfactory levels. However, there is a lack of knowledge on the relationship between different grinding parameters and the effect on the rails and the post-grinding evolution of roughness and wear. Rail undergoes significant levels of stress during grinding to remove any defects that appear during its life-cycle which can cause significant microstructural change. By developing a method of demonstrating rail grinding it will allow further investigation of the process and potentially the exploration of different grinding patterns. Moreover, an analysis of the roughness of wheel and rail is an input parameter in most modern simulation tools that could be associated with the coefficient of friction. This paper reports a laboratory demonstration of rail grinding followed by a series of tests to determine the wear of the rail and if there is a relationship between friction coefficient and roughness. The rail specimens that were ground have undergone a phase transformation and showed White Etching Layer (WEL) on the contact surface. This was found to initially act protectively for the rail disc reducing the wear rates, but then contributed to crack formation. No clear long-term correlation was identified between the coefficient of friction and roughness during the testing, however a relationship could be drawn when test periods were studied individually.