Wheel flange lubricant performance: A physicochemical and tribological assessment under varying environmental conditions

Flange lubrication prevents derailment, reduces wear and noise, and improves railway efficiency. Therefore, this study examines lubricant performance in Swiss metre-gauge railways under sharp curves, steep gradients, varying weather, and high axle loads. Findings help to optimize lubrication, cut maintenance costs, and extend component lifespan. Within the study, different flange lubricants used by metre-gauge railways in Switzerland are investigated in terms of physicochemical properties and tribological performance. Rheometer measurements are conducted to identify dynamic viscosity at various temperatures occurring in the field (−10°C to +60°C). Adhesion is evaluated using a novel tackiness test under varying temperatures and rail surface conditions. With respect to tribological performance, twin disc tests are performed by a high-load twin disc test rig. To picture the challenging conditions in Swiss metre-gauge railways, the parameters include high contact pressures, high slip, and demanding environmental conditions. The results reveal substantial differences among flange lubricant products. The work points out that cost-efficient laboratory tests enable effective preliminary screening before tribological evaluation and field test campaigns. Findings highlight the critical roles of environmental conditions such as temperature and humidity significantly influencing lubricant rheology, adhesion, and tribological performance.