Leaves on the line: Characterising leaf based low adhesion on railway rails

Abstract

Work was carried out to generate wheel/rail interface creep force data with the presence of leaf contamination. To enable this. the HAROLD full-scale wheel/rail test rig was upgraded to give friction measurement capability and methods for creating leaf layers were also developed. A unique dataset has been created not previously available for full-scale test conditions and leaf layers. The work has shown the importance of the shear induced in the brake tests for creating the black, well-bonded leaf layer. It was found in the tests that ultra-low adhesion was achieved in all tests with leaves regardless of load applied and speed. The friction was also low for a number of braking events, even when the layer had been partially removed.