All three types were ultimately derived from the earlier Series 52 locos, representing a faster version of the design, allowing for 140 km/h usage instead of 120 km/h.

After the Second World War, the National Railway Company of Belgium resumed railway operations using mostly steam locomotives that had survived the conflict as their primary means of transport, mostly locomotives built during the war (Types 25 and 26, based on the German "kriegslok") or others that were built in Canada (Type 29).

By the end of the 1970s, NMBS/SNCB responded to the complaints of their locomotive engineers over various inconveniences with the driving position of these locomotives: they were very uncomfortable and their prominent hoods along with the position of the controls on the right side of the units while driving in the left lane hampered visibility of the track-level signals along the line that were flush with the ground.

They were still allocated for some time to the Stockem depot, used for local services to the Burgo Ardennes paper mill in Harnoncourt or the Valvert factory in Etalle in particular[citation needed].

The arrival of Series 77 locomotives in Stockem sounded the death knell for the "Big Noses" and led to them being parked.

It wears a dark green livery with yellow stripes and is decorated with a winged wheel at the front.