The invention is directed to remotely-controlled manipulator carrier systems for use in maintaining and servicing process equipment housed in large-area cells affected by radioactivity wherein industrial processes are conducted. The cells are part of a nuclear facility for reprocessing irradiated nuclear fuel materials. The process equipment is arranged along mutually adjacent walls of the cell and so defines a canyon-like passageway extending in the direction of the longitudinal axis of the cell. The system includes a first overhead bridge crane having a trolley movable thereon in a direction transverse to said longitudinal axis. The trolley includes a hoist for lowering and raising a hook for engaging and moving a component of the process equipment in a first vertical plane transverse to said axis. A second overhead bridge crane is disposed beneath the first bridge crane. Tracks are provided for guiding the bridge cranes in the enclosure in respective horizontal planes and in the direction of said longitudinal axis. The second overhead bridge crane includes an elongated supporting member arranged transversely to said axis above the passageway and engaging the track for movement therealong. A manipulator assembly includes a mast connected to the elongated supporting member and extends downwardly into the canyon-like passageway from the supporting member. The supporting member and the mast conjointly define a second vertical plane transverse to said axis. The manipulator assembly further includes a manipulator or performing manual-like operations on the process equipment, the manipulator being mounted asymmetrically on the mast so as to be on one side thereof and in a third vertical plane transverse to said axis. The first bridge crane is movable along the track to bring the first vertical plane into coincidence with the third vertical plane so as to permit movement of the hook in the third vertical plane clear of the transverse elongated supporting member whereby both the manipulator and the hook can be brought simultaneously to a predetermined work location at the process equipment.