In 1971 two prototypes of the class 614 were built, which were a further development of the VT 24/VT 34. They have been designed to offer the greatest possible interoperability with the predecessor while still being able to take advantage of the latest developments. The peopulsion system remained basically the same as that already described in the predecessor with boxer engines arranged under the floor. In contrast to the later production vehicles, the prototypes were again given a curvature-dependent tilting control. In contrast to the predecessor, the car body tapers towards the top in order to be able to maintain the loading gauge even with a steep incline. In the series, the approval for 140 km/h was retained even without this technology.

The biggest changes compared to the predecessor were in the area of design. Even when looking from the outside, clear differences can be seen, especially on the streamlined front. The interior has also been thoroughly revised, for example individual seats with fabric covers were now installed. Trains could still be made up of two to four cars, with three-car trains with a trailer usually predominating and being used exclusively later on.

Since the technical changes to the predecessor were limited, both types could be used together with almost no restrictions. In some cases, not only entire units of both types were used in multiple, but multiple units were also formed from different vehicles. One of the combinations was a train consisting of a class 614 motor car with a matching trailer (914), followed by a trailer from the predecessor VT 34 (934) and the matching control car (634). At the time of the DB AG, the trains were modernized and some got new Caterpillar engines, each with 448 kW, since the engine power was classified as far too weak, especially with trailers on gradients. The retirement of the last of the 42 units built was completed in 2010. Two pieces were sold to Romania.