Leaves on the line: Characterising leaf based low adhesion on railway rails
Roger Lewis, Gerald Trummer, Klaus Six, Julian Stow, Hamid Alturbeh, B. Bryce, P. Shackleton, Luke Buckley Johnstone
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.