"In operating condition in the early 1970s / In order to cover fast passenger trains in the narrow network of D trains, the Deutsche Reichsbahn ordered a total of 55 class 01.10 locomotives in 1939. The advantage of the express steam locomotives was the top speed of 140 km/h. Even on gradients, the locomotives maintained a constant speed of around 100 km/h for passenger trains. In the course of the conversion at the Deutsche Bundesbahn to oil firing, the steam engines were given the series designation 012 from 1968."