Research methodology for evaluation of top of rail friction management in Australian heavy haul networks

Managing the coefficient of friction at the wheel-rail interface through lubrication is an accepted practice in railway systems. The coefficient of friction between the top of the rail and the tread of the wheels is not addressed well, with the traction, braking and some steering forces causing significant rail and wheel damage. Top of rail friction management uses friction modifiers to control the coefficient of friction on the top of the rail to within a defined range, and is being used in some North American rail networks with beneficial results. In Australia there has been limited use of top of rail lubrication. This has usually been applied to improve steering forces and mitigate wheel squeal. In recent times, application of top of rail lubrication in heavy haul networks has created significant interest among Australian rail agencies. This research project seeks a holistic understanding on top of rail lubrication and management of wheel-rail friction in the Australian context. A systematic approach for experimenting and analysing several friction modifiers was developed in this study. The approach used pin-on-disc tribometer based laboratory experiments, a Matlab study for three dimensional analysis and Gensys simulation to correlate the relationship between wheel-rail wear and the use of various friction modifiers.