The locomotives BB 12000/13000 are intended for mixed freight and passenger traffic, while the locomotives CC 14000/14100 are reserved for heavy freight traffic with a maximum speed of 60 km/h. The external appearance of all these locomotives is uniform, featuring a single driver's cab in a central position, topped by two pantographs, and two removable motor hoods with a conical shape that facilitate access to the control systems. The driver's cab can be used in both driving directions, allowing for manual control of the devices and simplifying the 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, and an unusual blue paint scheme for locomotives give all these locomotives a common family appearance, earning them the nickname "iron" or less commonly "ham cutter," because the shape of the traction manipulator resembles the ham cutter disc found in butcher shops. The BB 12055, built by Alsthom for the mechanical part and by Schneider-Westinghouse for the electrical part, was delivered and put into service on July 27, 1958, at the Thionville depot. Subsequently, it was assigned to the Mohon depot in April 1959, to the Lens depot in September 1979, and back to the Mohon depot in May 1983, before being assigned to the Lens depot for the last time in September 1993. It was withdrawn from service on March 25, 1994, after 4,271,818 km.