Laboratory simulation of low-adhesion leaf film on rail steel

Low-adhesion (i.e., low-friction) problems continue to plague the modern railway, particularly in autumn when leaves on the line and damp conditions combine to form a low-adhesion contaminant film on the railhead. Sudden drops in adhesion can cause havoc with timetables, and can lead to accidents electrical insulation by contaminants can cause problems with track circuitry. Using laboratory twin-disk testing, a number of techniques for reproducing the leaf-film have been tried, and the adhesion behaviour of the resultant contaminant films is investigated. Misty conditions are found to be the best for producing low-adhesion leaf films.