Product Features and Details
Whereas during the first years after World War II the focus of the Deutsche Bundesbahn was on repairs of rolling stock, lines and buildings, with the beginning of the 1950s attention shifted to renewal of the trains. For passenger services on not electrified lines, the first prototypes of main line diesel locomotives such as the class 220 were commissioned in 1953. Subsequently DB ordered the rail industry to develop new DMUs in order to replace pre-war classes and steam traction.
In 1961 MAN and Waggonfabrik Uerdingen both delivered two prototypes each. Even though they were quite similar, they can be distinguished easily by the different front design. DB put the prototypes into service as class VT 23.5 (MAN) and class VT 24.5 (Uerdingen). After the newnumbering scheme the prototypes were listed as class 624 together with the regular units. The prototypes underwent intensive tests, including comparison to conventional push/pull trains with DB Class V 100.
The regular trainsets were delivered from 1964–1968 and were produced jointly by both manufacturers. Only minor changes were made to the prototype design. A total of 80 front cars and 55 middle cars were delivered, allowing the use of 40 three-part or two-part trainsets. Starting in 1968, a number of units were equipped with penumatic shock absorption and passive tilting systems. These units were listed as class 634 and approved for a higher speed of 140 km/h. As the tilting system turned out to be of limited use, clearance allowing only very limited tilting, in 1979 the tilting system was removed .