Class 624 (VT 23 / 24)

Updated: August 2026 – Before modern regional railcars dominated the picture, vehicles like Class 624 from the Deutsche Bundesbahn’s VT 23/24 programme ran on non-electrified branch lines. Angular bodies, a diesel soundtrack, a centre car between two power cars. This page shows you how to place this design, how the old VT/VS/VB system works, and what’s still left of it today.

What is Class 624?

Class 624 is a diesel railcar for local services, developed from the Deutsche Bundesbahn’s VT 23/24 programme of the 1960s. The vehicles ran in multi-car formation: power cars with a driving cab at the ends of the train, with a centre car without its own driving cab in between.

Its job was clearly defined. On lines where a locomotive-hauled train was too much effort, a self-propelled railcar was meant to offer an attractive service – flexible in length, quick to turn around, with no need to run the locomotive round. The further development of this idea led to Class 614, which carried the concept on through the 1970s.

In the vehicle classification system the 624 sits with the diesel railcars under the UIC type code 95 – the first two digits of the twelve-digit vehicle number. Being a historic vehicle makes no difference to that: the code describes the type of traction, not the year built.

VT, VM, VS, VB: the system behind older railcars

Anyone used to modern multiple units reliably trips over one thing with historic vehicles: a train doesn’t carry one number, but several. Each type of car has its own series.

Abbreviation	Meaning	Engine	Driving cab
VT	Verbrennungstriebwagen (diesel power car)	yes	yes
VM	Verbrennungs-Mittelwagen (diesel centre car)	no	no
VS	Verbrennungs-Steuerwagen (diesel driving trailer)	no	yes
VB	Verbrennungs-Beiwagen (diesel non-driving trailer)	no	no

This logic explains why vehicle lists show several class numbers for a single train. For spotters that has a very practical consequence: anyone who only notes down the power car’s number has only documented half the train. You’ll come across the same system with railbuses like the Uerdingen railbus of Class VT 98, where power car, driving trailer and non-driving trailer form a flexible modular system.

How to identify the vehicle in the field

How to work through features in a sensible order instead of getting stuck on details is described in the guide to identifying rolling stock classes.

Spotting and photographing a museum vehicle

Without regular service, the task changes fundamentally: the date is the scarce resource, not the location. Anyone looking to get started should begin with heritage operators such as the Darmstadt-Kranichstein Railway Museum, which publishes its running days well in advance.

Three points make the shot better:

• Show the whole train formation. The multi-car formation is the defining feature. A pure front-on shot throws away exactly that information.
• Capture era-appropriate details. Markings, livery and fitting-out details date the vehicle in time – often more important for later documentation than the perfect angle.
• Take a second shot with the surroundings. Another photo with a station sign or the line’s surroundings keeps the sighting traceable years later.

How to keep such photos permanently organised instead of losing them in folders is described in the guide on building a photo archive for spotters. Dates for museum and special workings can be found via the article on finding special trains and special workings.

Reading old designations: VT 24 becomes 624

Historic vehicles often carry two names in the literature – and anyone who doesn’t know the connection takes them for two different classes. It’s especially pronounced with the 624, because both designations are still used side by side today.

The Deutsche Bundesbahn’s older scheme worked with letters and numbers: VT for Verbrennungstriebwagen, followed by a type number. VT 24 was therefore not a single vehicle, but a type group. When the switch was made to fully three-digit, computer-readable class numbers, these vehicles became, among others, the 624 – the same vehicles, a new data panel.

This switch has a very practical reason: a numbering scheme of plain digits can be processed by machine, one made of letter abbreviations can’t. Exactly the same thinking lies behind today’s twelve-digit vehicle number, whose first two digits give the type – 95 for diesel railcars, 94 for electric multiple units, 92 for diesel locomotives.

For your own research that gives a useful rule: older sources speak a different language than newer ones. Anyone reading about a historic vehicle should know both designations and try both when searching. Otherwise you’ll miss half the available information.

A second consequence concerns the markings on the vehicle itself. Vehicles preserved for museum use are often restored to a particular condition – and the markings of that era belong with it. A vehicle may therefore be lettered as VT 24 even though it’s listed as 624 in registers. That’s not a contradiction, but a deliberate decision by the operator.

For your own documentation that means: note down what’s actually written on the vehicle, and add the classification separately from that. That way it stays clear what you actually saw and what you concluded from it – a principle that’s especially valuable with historic vehicles.

Common mix-ups and how to rule them out

The later generation that replaced these vehicles in everyday service includes Class 628 / 629 – there you’ll find the same basic idea in a considerably more modern form.

Conclusion

Class 624 is a vehicle for anyone who wants to understand what German diesel-powered local services looked like before the era of standard multiple units. Identifying it is straightforward – styling, diesel roof, data panel – but catching sight of one is purely a question of timing. Anyone who does should note down every vehicle number, not just the power car’s.