Electric train traction units can behave as generators during brake, transforming part of the kinetic and potential energy into electrical energy.

 

Once generated, this energy could be used for auxiliary services supplying or other elements of the rail system such as trains, beacons, traffic lights or repair shops. It could be also accumulated during a short period of time or even be returned to the public main.

 

Furthermore, from the economical point of view, it would be useful to determine the energy savings that would supose the inclusion of this technology, in order to establish a comparation and identify in each case whether it is advisable to make the necessary investments.