The VT 24 is a diesel-hydraulic multiple unit consisting of two to four cars, which gained notoriety by testing the tilting technology on a few examples. It emerged from the VT 23, of which four prototypes were built in 1961. The production model was finally built in series between 1964 and 1968 in a total of 80 motor cars and 55 trailers and designated as the VT 24 or class 624/634.
The multiple units each consisted of two motor cars and usually one trailer, but could also be used without a trailer or with two of them. For optimal use of space, the entire propulsion technology was installed under the floor. The engine was a boxer from MAN, which was ideally suited for this design due to its flat design. As already mentioned, some vehicles were equipped with tilting technology, for which they received air suspension. However, since the car body did not taper towards the top, the maximum angle of inclination had to remain within a very limited range with regard to the loading gauge. The vehicles converted in this way were designated as class 634 and certified for a top speed of 140 km/h. However, since the benefit of the tilting technology was too small compared to the high effort, all of them were later reverted. A special feature of the classes 624, 634 and the 614 with the same engine is that all vehicles could be used together in multiple. A total of up to six power cars could be used at the same time.
They were used in various areas of Germany for a long time, but from the late 1990s they were replaced with newer vehicles. As a result, some of them were retired, but they were also used as a substitute for vehicles that were not available at the time. Others were also sold to Poland and Romania. Their use ended in Poland in 2012, but they will be used in Romania for longer. The last ones were retired by the DB in 2005.