Analytical and experimental investigation of composite pads created by using coke dust against the fading problem in railway vehicles

In this study, the effects of using coke dust in brake pad mixtures against the problem of friction coefficient reduction occurring at high temperatures in railway vehicle brake pads were investigated. For this purpose, the average friction coefficients and wear rates of the brake pads produced by using different amounts of coke dust were tested with the help of a dynamometer at different temperature values and the brake pad mixture containing coke dust with optimum ratio was determined. Brake pads with optimum coke dust ratio were tested in a train set under real railway conditions and the stopping distances of the train set and the temperatures during braking were measured. Using the stopping distances measured during railway tests and the average friction coefficients of the brake pads were analyzed analytically and compared with the dynamometer results. As a result of these tests, it has been observed that the coke dust material reduces the friction coefficient at low temperatures, but increases the friction coefficient at high temperatures and significantly reduces the amount of wear.