Conveying and retaining apparatus

In an apparatus suitable for transporting and retaining payloads on ferrous metal surfaces using electromagnetic holding devices, more particularly a pilot lift on the outboard walls of ships having at least one electromagnet disposed at a reduced distance from a surface to be moved over by running gear on a bearing frame adapted to receive the payloads, the improvement comprising an electricity generating unit for providing power to the electromagnet being mounted on said bearing frame, said generating unit comprising a D.C. generator drivable by a compressed-air motor, said generator capable of producing electric power for the electromagnet, and being disposed on the bearing frame.