In 1922, the Deutsche Reichsbahn began to develop a renumbering plan to standardize the numbering of steam locomotives that had been taken over from the state railways (Länderbahnen).
The development of this scheme was discontinued because it was seen that there would be problems in practically adopting it.
The second, provisional, renumbering plan of 25 July 1923 was very like the final version of 1925 in its basic structure.
The third and final renumbering plan of 1925 differed from its predecessor primarily in that all the locomotives retired up to that point – in some cases entire classes – were deleted; in addition several mistakes in the numbering were corrected.
With the exception of Bavarian classes, new locomotives built after 1923 were delivered from the outset with their new operating numbers.