Abstract: A control system for a conveying apparatus of a type consisting of one or more independently movable carriages supported on a rail extending along a series of treating stations, and wherein each carriage has one or more independently movable lift mechanisms thereon for depositing and removing racks with workpieces at the stations. In one embodiment, the programming device on the carriage for providing sequentially-phased movement of the carriage and lift mechanisms is advanced by a transferring motor which is actuated in response to the tripping of sensing devices on the carriage indicating the position of the carriage relative to the stations and the up and down position of the lift mechanism.The programming devices of each carriage, if a plurality of carriages are used, are interlocked to maintain them in sequence and a timer is employed to control portions of the operating cycle duration.