The BB 12000/13000 locomotives are intended for mixed freight and passenger service, while the CC 14000/14100 locomotives are reserved for heavy freight traffic with a maximum speed of 60 km/h.The external appearance of all these locomotives is unified with a single driver's cab in a central position surmounted by two pantographs, and two removable engine hoods of tapered shape facilitating access to the switchgear. The driver's cab can be used in both directions of travel, allowing manual control of equipment and simplifying wiring. Two chassis (one for the CC and one for the BB), two types of bogies (one for the CC and one for the BB) despite different engines, an unusual blue livery for locomotives, give a common family look to all these locomotives which are nicknamed "iron", or more rarely "ham cutter" because of the shape of the traction manipulator resembling the ham cutter disc that was found in the butcher shops. The BB 12055 built by Alsthom for the mechanical part and Schneider-Westinghouse for the electrical part, was delivered and put into service on July 27, 1958 at the Thionville depot. She was successively assigned to the Mohon depot in April 1959, then to the Lens depot in September 1979, and again to the Mohon depot in May 1983 before her last assignment to the Lens depot in September 1993. She was written off on March 25, 1994 after having covered 4 271 818 km.