Abstract: A controlled power system is in a train having electric controlled pneumatic (ECP) brakes on cars of the train connected to a trainline which carries electric power and control signals and having at lease one auxiliary device on some of the cars. The power system on a car having the auxiliary device includes a power module connecting the auxiliary device to a source of power when activated; and a first controller, including a transceiver, for activating the power module to the connect the source of power to the auxiliary device in response to a power up signal on the trainline.