This standard prescribes the electrical interface between the components comprising the auxiliary power systems and their electrical interface with other train-borne systems. As such this standard treats the auxiliary power system components (static inverters and converters, low voltage dc power supplies, back-up battery systems and battery chargers) as black boxes and address only their interface requirements. It does not provide standards or recommendations for the following: 1) Rotating machinery, such as motor alternator sets 2) Motive power systems or auxiliary power systems required for locomotives 3) Mechanical mounting or vibration isolation of equipment 4) Car-body wiring, branch circuits, circuit breakers and protection devices to interconnect the auxiliary power components with other car-borne equipment.