imported materials. These were the so-called war locomotives (Kriegslokomotiven and Übergangskriegslokomotiven). In the absence of a good highway network and trucks, Germany relied heavily on the railways, supplemented by slower river and canal transport for bulk goods. The rail yards were the main targets of the "transportation strategy" of the British and American strategic bombing campaign of 1944–45, and resulted in massive destruction of the system. Transition period (1945–1949) After World War II, Germany (and the DRG) was divided into 4 zones: American, British, French and Soviet. The first three eventually combined to form the Federal Republic of Germany (the West) and the Russian zone became the German Democratic Republic (the East). German territories beyond the Oder were ceded to Poland except for the northern part of East Prussia, which was ceded to the Soviet Union in 1945. Deutsche Bundesbahn (1949–1994) From 1949, the new governments assumed authority for railway operations. The DRG's (or DR's) successors were named Deutsche Bundesbahn (DB, German Federal Railways) in West Germany, and Deutsche Reichsbahn (DR, German State Railways) in East Germany kept the old name to hold tracking rights in western Berlin. Unlike the DRG, which was a corporation, both the DB and the DR were federal state institutions, directly controlled by their respective transportation ministries. Railway service between East and West was restricted; there were around five well-controlled and secure checkpoints between West and East Germany, and about the same number between East Germany and West Berlin. Four transit routes existed between West Germany and West Berlin; citizens of West Berlin and West Germany were able to use these without too much harassment by the East German authorities. The DB started in 1968 with changing the locomotive and passenger car serial numbers to the UIC norm. In 1970 the DR followed. The DB started experimenting with the Intercity trains in a new livery (bright orange). In 1988 the prototype InterCityExperimental (ICE V) set a new German railway speed record of 406.9 km/h (254.3 miles/h) on the new high speed line between Fulda and Würzburg. In 1991 the new high speed lines Hannover-Fulda-Würzburg (280 km/h) and Mannheim-Stuttgart (250 km/h) were opened for service including the new ICE 1 train sets. Deutsche Reichsbahn (DR) (1949–1994) Deutsche Bahn (1994–present) In 1989, the Berlin Wall fell. Train frequency rapidly increased on the existing East/West corridors; closed links which had formerly crossed the border were re-opened. On 3