Railway Braking Systems. Braking Control

Rail transport is characterized by a number of specific features, including :

• the moving object, i.e. the rail convoy (or train), uses a guideway (the track) which requires it to travel between two other convoys, which travel either in the same direction as it (double-track line), or in the opposite direction (single-track line). Except in the case of "on-sight" operation, such as on tramway networks, its movement is therefore governed by signaling systems that minimize to an acceptable level the risk of overtaking or head-on collision between two trains. Consequently, braking control must be designed to ensure operation and performance compatible with the requirements of the various signalling systems encountered in operation;

• the mobile object is a convoy, i.e. an assembly of vehicles that may be identical or very different. These convoys can range in length from a few dozen meters to several kilometers. The braking control system must therefore be designed to ensure operation and performance compatible with very different convoy lengths and types;

• a rail convoy may be made up of vehicles from very different origins in terms of ownership, and it is therefore important that braking control meets interoperability standards or specifications, enabling vehicle exchanges between trains from different operators (within the same country, or between countries).

We present here the general architecture of braking system control as it is now defined by European standards, and as it is generally presented throughout the world. We then show how this general architecture can be broken down into three main types of braking system, each of which has been developed to adapt to different operating conditions and interoperability constraints.