However, the third order for another 103 machines was cancelled in 1941, because the outbreak of the Second World War favoured the construction of simpler wartime locomotives, the so-called Kriegslokomotiven.

From 1950 therefore several Deutsche Bundesbahn machines were equipped with an outer firebox with a combustion chamber and a mechanical underfeed stoker (Rostbeschicker).

The engines with operating numbers 45 010, 45 016, 45 019, 45 021 and 45 023 were provided with welded boilers and underfeed stoker equipment.

In East Germany, the Deutsche Reichsbahn's sole example, 45 024, was rebuilt into high pressure variant and renumbered H 45 024.

Following replacement of the boiler and the introduction of mechanical stoking the true qualities of this locomotive became clear.