The effects of friction management materials on rail with pre existing rcf surface damage

Hydro-pressurisation and crack face lubrication are processes by which liquid materials (e.g., water), enter pre-existing RCF cracks and under wheel/rail contact pressure and cause accelerated crack growth, leading to spalling and shelling on rail and wheels. Thus, any liquid material added deliberately to the wheel/rail interface should be considered carefully in terms of the potential for aggravating RCF damage. This study compares the impact on hydro-pressurization and crack face lubrication of different types of materials designed for application to the top of rail using twin disc testing. One type of FM material is water-based, drying providing solid particles to the rail-wheel contact. Two other types are oil or oil-plus-water-based (hybrid material) that do not naturally dry and have been introduced more recently to the market. In addition, a commonly used gauge face lubricant (grease) was evaluated.