West German 01 class Pacific with a passenger train at Weiden in 1969

Appropriately the km post also reads 01.

The Deutsche Reichsbahn-Gesellschaft’s BR 01 steam locomotives were the first standardized (Einheitsdampflokomotive) steam express passenger locomotives. The idea behind standardization is to reduce cost and make repairs easier and quicker. A total of 231 examples were built by companies across Germany. They had the 4-6-2 “Pacific” wheel arrangement in the Whyte notation, or 2′C1′ h2 in the UIC classification. 

The BR 01 was a 2-cylinder locomotive, but as a test 10 locomotives were built with a 4-cylinder configuration, these were renumbered in BR 02. The 2-cylinder version was favored after long testing because it was easier to maintain running compared to the 4-cylinder version. The main batch of the BR 01 were delayed in the 1920s because the infrastructure of the Deutsche Reichsbahn wasn’t ready for these locomotives. Turntables needed to be lengthened and railway lines needed to be strengthened to be able to support the 20-ton axle load locomotives.

From 1938 there were 231 BR 01 locomotives available for prestigious express train duties across Germany. The 10 four-cylinder BR 02 locomotive version (01 111, 01 233–241) were converted to two-cylinder BR 01 models between 1937 and 1942. Since there were so many routes that still had axle load restrictions, which were too low for the 01 service, in the early 1930s, a third variant was produced: the BR 03 designed with a two-cylinder engine and axle load of 18 ton. A total of 298 BR 03 locomotives where built. Launched in 1939, the three-cylinder DRG Class 01.10 was a further development of the 01.

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