DB Class VT 24

DB class 624 / 634

A class 624 at Oldenburg main station

Type and origin Power type Diesel-hydraulic Builder MAN AG, Waggonfabrik Uerdingen Build date 1961 (prototypes) 1964-1968 (regular)

Specifications Configuration: ​  • AAR B'2' + 2'2' + 2'B' (standard configuration) Gauge 1,435 mm (4 ft 8 1⁄2 in) Axle load 12 t (12 long tons; 13 short tons) Prime mover MAN Engine type Diesel engine

Performance figures Maximum speed 120 km/h (75 mph) (class 624) 140 km/h (87 mph) (class 634) Power output 2x 331 kW (450 PS; 444 hp)

Career Operators Deutsche Bahn, PKP Locale Germany Poland Retired 2005

Class 624 and class 634 are types of diesel multiple unit, originally operated by Deutsche Bahn.

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 new numbering 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 pneumatic 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.

In 1970 a number of trainsets derived from class 624 were delivered to Yugoslavia (Slovenia) as SŽ class 711. They are still in use by Slovenian Railways.

Upon entering service the new class 624 units were often used for fast regional and express trains in various parts of Germany. This changed gradually and by 1980 nearly all of the units were based in Osnabrück und Braunschweig, performing duties on regional and local lines. Regional and local passenger traffic in the Harz region was carried out almost exclusively by these trainsets.