Wojciech Sawczuk

Selected issues of operational use of rail disc brake

This article describes disc brakes, which in comparison to traditional block brakes are more often used in rail vehicles. Because of numerous advantages in comparison to a traditional air block brake, disc brakes, are more and more often utilized in passenger carriages and other railway vehicles. Stable and constant – in the whole speed range – coefficient of friction μ, with the value: μ =0.35 is a basic advantage of disc brake systems [7]. Attempt to increase train speed, triggers application of greater braking power i.e. braking systems rapidly absorbing and dispersing stored heat energy. For stimulation of cooling processes of friction set (brake disc and friction pad), discs with ventilation canals shaped by various vanes, are used. Thanks to such solution discs take off about 40% [4] of heat generated during braking. However, natural ventilation causes losses of energy for rotation of the disc during ride with switched off brakes, which is especially important for trains with little frequency of brakings and in cases when the profile of the track does not stimulate long-lasting braking.