Tribological and Physiochemical Properties of Greases for Rail Lubrication

Abstract

Rail lubrication is vital in determines the friction, wear and noise level in the wheel and rail contacts. In general, the primary function of a rail curve grease is to minimize friction between the contact as well as to protect side wear of rails on a curved track. In this study, three commercially applied railway greases were identified and the wear and friction behavior, as well as the load-carrying ability, were investigated. Before that, the grease's physiochemical properties in terms of the consistency and drop point, as well as the element content, were also examined. The tribological investigation of the greases was also carried out using four-ball wear tester. In this test, the wear preventive (WP) and extreme pressure (EP) properties of the grease were measured under sliding actions between the balls, and the wear surface analysis was also carried out. The tests results explained that the rail curve greases are very soft in texture yet have stable structure over a high-temperature range. The greases also presenting low friction coefficient; ranges between 0.070 to 0.090, and acceptable wear scar diameter indicating the good anti-friction and anti-wear properties. High load-carrying ability up to 400 kg is also the significant properties for a rail curve grease to perform as the desired functions.

Keywords

• wheel-rail contact
• bio-grease
• elemental analysis
• four-ball wear test
• wear preventive
• extreme pressure