In 1925, when the standard locomotive program was still young, a passenger locomotive for branch lines with an axle load of 15 tonnes was to be developed. With a maximum speed of 90 km/h, this should also be able to be used in front of light trains on main lines. Above all, this locomotive was intended to replace a large number of different Länderbahn locomotives that had now reached an advanced age. Since there was no consent as to whether a tender locomotive or a tank locomotive should be developed, the class 24 was created as a tender locomotive and the class 64 as a tank locomotive.
Both classes were identical in terms of running gear with the leading and the three driving axles and also had the same boiler. The 64 also had a trailing axle that carried the coal supplies and part of the water supplies. As a result, the 64 could also run backwards at 90 km/h, which was not possible with the 24 with the tender. Both carrying axles were only mounted in Bissel frames on almost all locomotives, only the last ten had a Krauss-Helmholtz bogie installed at the front.
In 1928 alone, 188 were made by a large number of manufacturers and by 1940 the number had risen to 520. Another order for 90 was canceled in favor of more urgently needed freight locomotives. A locomotive built in 1940 was delivered directly to the Elmshorn-Barmstedt-Oldesloer Eisenbahn (EBOE).
After the Second World War, 393 were still existing in Germany. Of these, 278 went to the Bundesbahn and 115 to the Reichsbahn. 37 were in Poland and thus went to the PKP as OKl2. These three railway companies retired them in the mid-1970s. Individual locomotives could be found in Czechoslovakia, the Soviet Union and Austria, which were used for a longer time. Today there are still 19 left, three of which are operational.
