Performance analyses of brake blocks used by Indian Railways

Friction characteristics of cast iron, two “L-type” and two “K-type” composite brake blocks, used by Indian Railways for tread braking, were obtained experimentally under dry conditions using full scale stop braking experiments. Apparent friction coefficient of brake blocks was seen to depend on brake load, sliding speed, as well as sliding distance. Brake block friction characteristics along with traction-slip and running resistance characteristics for wagons and locomotives were used to estimate frictional heat generation rates at brake block-wheel and rail-wheel interfaces as a function of brake block type, brake load, number of wagons, tonnage per axle, nature of terrain (flat, uphill, downhill, etc.), train speed and time lag in braking. Braking performance was more consistent for cast iron brake blocks than that for composite brake blocks. Further, thermal loads on locomotive wheels were also lower for cast iron brake blocks, particularly with time lag in braking.