The present invention concerns a method and system for reducing the electric power consumption of a railway system comprising at least one catenary, trains and at least one substation connected to sections of catenary and providing electric power to the catenary, wherein during the braking of the trains, the braking trains provide electric power to the catenary. The substation is associated to one device for reducing the electric power consumption and the invention: detects the presence of a braking train in one of the section connected to the substation, interrupts the electric power provided by the substation to the catenary if the presence of the braking train is detected, detects the absence of braking trains in each section connected to the substation, means for enabling the electric power to be provided by the substation to the catenary if the absence of braking trains is detected.