3-piece print variant of the BR 624 in mint green of the DB AG Era V. The series VT 23 and VT 24 refer to diesel multiple units of the Deutsche Bundesbahn, consisting of two powered end cars and up to two middle cars, which were designated as VM 23 and VM 24. In 1968, the multiple units were renumbered to the series 624, and the vehicles equipped with air suspension were designated as 634. The middle cars were subsequently designated as 924 and 934. A total of 80 multiple units and 55 middle cars were built by MAN and the Uerdingen Wagon Factory. In 1967, the first trials with track curve-dependent car body control began, leading to numerous VT and VM units being retrofitted with air suspension. The multiple units typically consist of two powered driving cars and one non-powered middle car. However, units can also be formed without or with up to two middle cars. A larger number of middle cars is not possible in passenger operation, but a maximum of three units/six machines can be operated in a train formation for multiple traction. From 2005 onwards, the multiple units were replaced by new vehicles and taken out of service.