The Deutsche Reichsbahn ("German Imperial Railway") – was the name of the German national railway created from the railways of the individual states of the German Empire following the end of World War I.
It was founded in 1920 as the Deutsche Reichseisenbahnen when the Weimar Republic (formally Deutsches Reich – "German Empire" – hence the usage of "Reich" in the name of the railway) took national control of the German railways, which had previously been run by the German states.
In 1924 it was reorganised under the aegis of the Deutsche Reichsbahn-Gesellschaft (DRG), a nominal private railway company, which was 100% owned by the German state.
In 1937 it was reorganised again as a state authority and given the name Deutsche Reichsbahn (DRB). After the Anschluss in 1938 the DR also took over the Bundesbahn Österreich (BBÖ, Federal Railway of Austria).
The East and West German states were founded in 1949. East Germany took over the control of the DR on its territory and continued to use the traditional name Deutsche Reichsbahn, while the railway in West Germany became the Deutsche Bundesbahn (DB, German Federal Railway). The Austrian Österreichische Bundesbahnen (ÖBB, Austrian Federal Railways) was founded in 1945, and was given its present name in 1947.
In January 1994, following the German union, the East German Deutsche Reichsbahn merged with the West German Deutsche Bundesbahn to form Germany's new national carrier, Deutsche Bahn AG, technically no longer a government agency but still a 100% state-owned joint stock company.
Read more about Deutsche Reichsbahn: 1920: Deutsche Reichseisenbahnen, 1924: Deutsche Reichsbahn-Gesellschaft (DRG), 1937: Deutsche Reichsbahn (DRB), 1938: Absorption of The Austrian Railways, 1939-1945: The Reichsbahn in The Second World War and The Holocaust, 1945-1949: Devolution of The Reichsbahn, 1949-1994: The Deutsche Reichsbahn (DR) in East Germany