There is disclosed a system for use in transport vehicles, comprising in combination an auxiliary power unit (APU) for a transport vehicle powered by a diesel engine and having a fuel system, an engine exhaust system and a battery powered electrical system; and a locator unit for use in a tracking and monitoring system for communicating over a communication network with the locator unit and with a remote location the APU, wherein the locator unit is attached to or installed within the APU.In another aspect there is disclosed an auxiliary power unit (APU) for a transport vehicle comprising an enclosure for housing and supporting the auxiliary power unit on the transport vehicle; an air-cooled diesel engine directly driving an air-cooled, brushless generator providing direct, simultaneous AC and DC voltage outputs; first and second air duct systems within the enclosure for separately conveying cooling air into and through the air-cooled, single cylinder diesel engine and the generator respectively; and an engine exhaust adapter wherein engine exhaust from the air-cooled diesel engine is directly coupled through the exhaust adapter installed in-line with an exhaust pipe of the transport vehicle between the engine of the transport vehicle and the muffler of the transport vehicle.