The class 24 was one of the few German tender locomotives which were developed directly for use on branch lines. In order to make the best possible use of the advantages of the standard program, it was developed together with the tank locomotive of the class 64. Both locomotives were almost identical except for the water tank on the 64 up to the cab.
In West and East Prussia, the Reichsbahn had an extensive network of branch lines that lay in the flat land and had long distances between stops. However, most tender locomotives could not be used on many of these routes because the axle loads were too high. This is how the 24 was created as a passenger locomotive with a 2-6-0 wheel arrangement, whose maximum axle load was 15 tonnes and which was designed for 90 km/h. With its long range, it quickly gained a reputation as a flat land racer, and it was also nicknamed the “steppe horse”. In comparison to other standard locomotives, the 24 stood out because the boiler was mounted relatively far forward, meaning that the cylinders and chimney were not at the same level. The construction of the chassis could be kept quite simple due to the small number of axles. The mounting of the leading axle in a Bissel frame and weakened flanges on the central coupled axle were sufficient to achieve good running characteristics.
A total of 95 pieces were made, which were delivered between 1928 and 1940. The 24 069 and 070 were designed as medium-pressure machines with a boiler pressure of 25 bar. The former got a two-cylinder compound engine and the latter uniflow cylinders. While the 070 was not convincing at all and was later reverted to the status of the production engines, the 069 achieved the lowest specific steam consumption of all standard locomotives. Due to problems with the higher pressure, both were later only operated at 20 bar.
Compound medium-pressure test engine 24 069 ##
Die Lokomotive, January 1936
Since the engines were purchased for the eastern areas of the Reich, 34 units came to the Polish State Railways after the end of the Second World War, which used them until 1976 under the designation Oi2. A larger part of 47 pieces came to the Bundesbahn, where they were all retired between 1960 and 1966. The Reichsbahn received only four engines, three of which had been retired before 1970. The only remaining 24 009 finally got the number 37 1009 and was sold two years later.