SUMMARY

When we speak of progress, of railway performance, we think first about traction and motorization, but we often forget braking. Without it, the recent progress in railway would not have been possible. 

For example, if we don't brake a made-up train of TGV travelling at 300 km/h, it needs more than 100 km to stop against 3.3 km with the present braking technologies. 

Originally, the braking of the first trains was operated manually by brakemen until the 1870's. At this time, George Westinghouse invented pneumatic braking by depression. The train driver alone could brake the whole train.  

Nowadays, the principle of this braking is still used and completed by the modern technologies such as electricity and electronics. 

Today, innovation and evolution permit us to use several types of brake according to the rolling stock and the use. Friction brakes on wheel, on disk or on rail transform the energy into heat; dynamic brakes convert the kinetic energy into electric energy. Finally, brakes with Foucault currents create magnetic fields, which are opposed to the movement of the train. 

Today, the railway braking is still the object of numerous studies. They are centred mainly on new materials, remote control … and aim to improve the speed, the length and the weight of trains.