Abstract: A self-charging continuous EOT power supply/battery pack operates from excess air pressure available in a train's air system. An electric generator is driven by compressed air from the locomotive that is transmitted through the air brake system of the train. The generated electricity is input to a circuit card assembly that regulates the output voltage and generator speed. The regulated voltage is supplied to the EOT electronics and also to a storage battery to recharge the storage battery, which provides peak operating power as well as back-up power if the generating system is inoperable.