Influence of surface roughness and contact temperature on the performance of a railway lubricant grease

An adequate railway lubrication strategy is an important maintenance procedure that leads to decrease friction and wear extending the service life of the wheel and rail materials, improving the wheel-rail contact, avoiding energy losses and therefore, decreasing costs. On the other hand, poor lubricantion practices lead to losses instead of savings. Moreover, there are many commercial railway lubricants, but there are not proper methodologies to test their performance under different contact conditions. This work aims to evaluate the effect of roughness and temperature on the friction coefficient of ER8 wheel and 115RE rail materials by applying different amounts of railway lubricant grease using a pin-on-disc tribometer and simulating a wheel-flange and rail-gauge contact pressure. For a well-lubricated contact, the results reveal that for the same contact pressure and sliding velocity, rougher surfaces yield a lower friction coefficient.