A Spectroscopic Drift-Ftir Study on the Friction Reducing Properties and Bonding of Railway Leaf Layers

Abstract

Leaves react with rail steel and form a tribofilm, causing very low friction in the wheel/rail interface. This work uses tribological testing with addition of leaf particulates to simulate the reaction and the resulting reduction in friction coefficient in the laboratory. Diffuse-Reflectance-Fourier-Transform-Infrared Spectroscopy was carried out on the organic material and the layers that formed on the twin-disc surface. Dark material, visibly similar to operational layers, formed along with a transparent thin film. This “non-visible contamination” has been reported to cause low adhesion problems on railways, but not previously characterised. This article discusses the nature of these layers and builds upon earlier studies to propose a degradation and bonding mechanism. This understanding could be used to improve friction management methods.

Keywords: friction, rail, Tribofilm, Tribology