Method and system for regulating the power demanded by a rail motor

1. Field of the Invention A method of regulating the power demanded by a rail motor including a current collector system cooperating with a catenary supplied with direct current power by power supply substations distributed along the track includes the steps of: measuring the catenary voltage Vcat at the rail motor, measuring the catenary current Icat at the rail motor, evaluating the no-load voltage Vcatof the substation supplying power to the catenary to which the rail motor is connected, evaluating the maximum power available to the catenary from the equation: where R is the resistance of the catenary, and limiting the power demanded by the rail motor to a power limit Plim less than or equal to the calculated maximum power Pmax.