Cologne, Münster (Westfalen) and Wuppertal were grouped into the in the British Zone under Director General Max Leibbrand in Bielefeld. French Zone In the French Occupation Zone, the railways were grouped into the Operating Association of the Southwest German Railways () with its headquarters in Speyer. The Operating Association included the railway divisions of Karlsruhe (in the US Zone), Mainz and Saarbrücken. After the Saarland was transferred from the French Zone and was given its own state railway – the Railways of the Saarland () – the rest of the network of the Saarbrücken division went into the new Trier division. After the Deutsche Bundesbahn was formed this Operating Association was merged with it. Soviet Zone The Soviet zone of occupation became a self-declared socialist state, the German Democratic Republic (commonly known as East Germany), on 7 October 1949. One month prior, on 7 September 1949, the railway systems in the three western zones (the Federal Republic of Germany), were reunified and renamed the (DB – German Federal Railways). On the formation of East Germany on 7 October 1949, the railway system in the Soviet Zone retained the name (DR), despite the connotations of the word "Reich". This was due to the designation of the in postwar treaties and military protocols as the railway operator in West Berlin, a role it retained until the creation of the unified DBAG at the beginning of 1994. Bizone and creation of the DB To conform to the formation of the Bizone in 1946 the Head Office of the Railways of the American and British Occupation Regions () was created. In 1947 it moved its headquarters to Offenbach am Main and called itself the in the United Economic Region (). Following the foundation of the Federal Republic of Germany, it was renamed Deutsche Bundesbahn. East German Deutsche Reichsbahn In the post-war years, the DR in East Germany continued to develop independently of the DB, but very much in parallel. The locomotive classification scheme, based on that of the DRG, was extended. The production, conversion and development of steam locomotives initially continued in earnest; older, especially ex- classes being rationalised and withdrawn from service. A major conversion () programme to update steam locomotives and rectify flawed, mainly wartime austerity, classes was carried out in the 1950s. Gradually, however, they were replaced by the more economical and easier-to-maintain diesel and electric classes. In general this happened