The DRB Class 42[note 1] was a type of steam locomotive produced for the Deutsche Reichsbahn.

Seventy of the class were captured during World War II by the Soviet Union; under Russian ownership they were given the classification TL (ТЛ).

They were built for duties on routes that were cleared for a higher axle load, because they were more economical there than the KDL 1 Kriegslokomotiven of Class 52.

Originally it was intended to build very large numbers of these engines, but the end of the Second World War put paid to that.

So after 1945, 16 engines were built for the Reichsbahn in the western zone by the Maschinenfabrik Esslingen ('Esslingen Locomotive Works').

Because of the resulting higher axle load, the engines were classified by the Deutsche Bundesbahn as Class 42.90 locomotives and given the operating numbers 42 9000 and 42 9001.