Key takeaways
- The 424 is a sibling of the 423, not a separate design – the same family, a different platform specification.
- The separator is boarding: the 423 is built for high S-Bahn platforms, the 424 for lower ones.
- 424 and 434 belong together: 424 are the driving cars, 434 the intermediate cars of the same unit.
- Against the 425/426, the operating environment helps: S-Bahn service versus classic regional service.
- The UIC type code 94 comes before the number and marks all these vehicles as electric multiple units.
Contents
Fact file
| Vehicle type | Electric multiple unit for S-Bahn services |
|---|---|
| UIC type code | 94 – electric multiple unit or railcar |
| Train formation | Two Class 424 driving cars, two Class 434 intermediate cars |
| Design | Four-part articulated unit with Jakobs bogies, fully walk-through |
| Vehicle family | Construction family of Classes 423, 424, 425 and 426 |
| Car body | Lightweight aluminium construction |
| Electrification system | 15 kV / 16.7 Hz AC |
| Maximum speed | 140 km/h |
Identifying features
Is this really the class in front of you?
- Four car sections, fully walk-through, with Jakobs bogies at the gangways
- Basic shape of the 423 family: compact, softly rounded front with a large windscreen
- Boarding area designed for a lower platform height than the 423
- Several wide double doors per side, S-Bahn-typical door density
- Vehicle number starts with 424 (driving car) or 434 (intermediate car)
Updated: August 2026 – It looks like a 423, runs like a 423, and still isn’t one: Class 424 is the sibling of the S-Bahn’s standard vehicle, built for different platform conditions. This page shows you what to look for and why platform height is one of the most useful – and most overlooked – identification features there is.
Family resemblance? The number decides.
With closely related classes, the vehicle number is the only permanently unambiguous detail – Traintrack keeps it on record.
What is Class 424?
Class 424 is a four-part electric multiple unit for S-Bahn services from the same construction family as Class 423/433. One unit consists of two powered Class 424 driving cars and two Class 434 intermediate cars. The train is an articulated unit with Jakobs bogies, fully walk-through, built in lightweight aluminium construction, and designed for 140 km/h under 15 kV / 16.7 Hz AC. The family was built by a manufacturer consortium that included Bombardier Transportation.
The decisive difference from the 423 isn’t in the technology but in the boarding design. While the 423 is tailored to high S-Bahn platforms, the 424 was procured for a network of Deutsche Bahn AG whose platforms sit lower – originally for the Hanover area. This one detail explains why a single design shows up under several class numbers.
Why platform height creates a class
A vehicle has to match the platforms it stops at. If the floor sits higher than the platform, it needs steps; if it’s level, boarding becomes step-free and passenger exchange much faster. Because different platform heights coexist across Germany, the same basic design exists in several versions – and so under several class numbers.
Watch the boarding
Do passengers step in level or over steps? That's a direct clue to the vehicle's design.
Read the platform
High platforms belong to classic S-Bahn operation, lower ones to regional and mixed services. The environment narrows things down a lot.
Count the door density
Many wide double doors per side point to an S-Bahn vehicle; fewer, differently spaced doors to regional services.
Read the number
Only the vehicle number finally separates 423, 424, 425 and 426. Everything before that is pre-sorting – if a very effective one.
The background is worth knowing because it reaches well beyond this one class. Several platform heights coexist in Germany, grown historically and varying by region. Classic S-Bahn networks were consistently brought to a uniform, high platform edge; regional and mixed-traffic services kept lower heights, because long-distance and freight trains run there too. A vehicle can’t serve both optimally: either the floor matches the high edge, or it sits lower and needs a step down at high platforms.
That’s why platform height is a genuine design feature and not just a matter of fittings. Anyone who reads it in the field has an identification feature that works independently of livery, markings and operator – and one that, unlike the operating network, barely changes over a vehicle’s lifetime.
How the twelve-digit vehicle number is built up and what each position means is explained in the guide to the UIC number. The general approach to identification is covered in the guide to identifying classes.
Where it fits into rail operations
An S-Bahn vehicle with lower boarding is a special case: it serves S-Bahn-like traffic in a network that isn’t consistently built to S-Bahn standard. For observation, that means platform height and train type don’t always line up as neatly as in classic S-Bahn networks.
| Location | Likelihood | Why |
|---|---|---|
| S-Bahn networks with mixed platform heights | high | Exactly the environment the design was built for |
| Terminus stations with turnaround time | high | Standing time allows shots of boarding, side and number |
| Major interchange stations | medium | Many trains, but short stops and tricky light |
| Classic trunk routes with high platforms | low | Vehicles with high-level boarding fit better there |
| Non-electrified lines | very low | No overhead line, no service |
Depot and network are changeable
Vehicles are reallocated, networks retendered, fleets swapped. Details about deployment area therefore date quickly. Use current sightings and real-time data when searching for something specific, and treat older lists as historical information.
Know what's running today
Community sightings show you the current picture – not the one from three timetable years ago.
Spotting and photo tips
For a class whose distinguishing feature sits in the boarding area, that’s exactly what should show up in the shot too. That’s unusual – and it’s what makes the pictures more valuable.
Photograph the door area too
A shot showing platform edge and boarding documents the class's actual distinguishing feature – front portraits don't.
Three-quarter view as your base shot
30 to 45 degrees off the vehicle axis shows front, side and door layout together. For multiple units, the most informative angle.
Choose a spot with a clear sightline
Displays, shelters and waiting passengers often hide exactly the area you want to show on S-Bahn platforms. Pick your position deliberately.
Secure the number separately
A tight extra shot of the side markings costs nothing and makes the sighting unambiguous – especially with family classes.
Safety before the shot
Even a shot of the boarding area doesn't warrant crossing the safety line. Platform edge and safe distance apply without exception, and track areas and operational railway land are off limits.
Which spot at the platform suits which perspective is covered in the article on choosing a photo spot at the platform.
Common mix-ups
The 424 is confused practically only with its own family members – for good reason, since the basic shape is the same.
| Confused with | Looks similar because | What sets it apart |
|---|---|---|
| Class 423/433 | identical construction family and front shape | the 423 is built for high S-Bahn platforms, the 424 for lower ones |
| Class 425/435 | same family, also four-part | the 425 is a regional vehicle with regional seating and a different operating environment |
| Class 426 | same front shape and design | the 426 is two-part – the train length is unmistakable |
| Class 422/432 | also a four-part S-Bahn articulated unit | a different development stage and its own number block |
It points to the 424 if …
- the train has four car sections and is fully walk-through
- the front shape matches the 423 family
- boarding is designed for a lower platform height
- the number starts with 424 or 434
Look more closely if …
- you can identify the family with confidence but can't decide between 424 and 425
- the platform has an unfamiliar height and boarding is hard to judge
- two units are coupled together and counting cars gets confusing
It isn't a 424 if …
- the train has only two car sections
- it consists of three separate car bodies with no gangway
- a separate locomotive is moving the train
Conclusion
Class 424 teaches a principle that reaches well beyond it: vehicles are distinguished not only by technology, but by the environment they’re built for. Platform height, door arrangement and boarding conditions often say more about a class than the front shape. Anyone who reads that can sort the whole 423 family cleanly – and only needs the number to confirm it.
In short
Four car sections, Jakobs bogies, the front shape of the 423 family, but boarding built for lower platforms: that's the 424. The final answer comes from the number on the side.
Keep an eye on the whole family
423, 424, 425, 426 – with Traintrack you see which units you already have and which are still missing.
Summary
- Class 424 is the four-part S-Bahn variant of the 423 family for networks with lower platforms.
- Design, front shape and interior layout largely match Class 423.
- Boarding height and operating environment help tell it apart, and the vehicle number settles it for good.
- Network and operator are changeable and so are no use as an identification feature.
Frequently asked questions
What's the difference between Class 423 and 424?
Both are four-part articulated units from the same construction family. The main difference lies in the boarding design: the 423 is tailored to high S-Bahn platforms, the 424 to lower platform heights. From a distance they look very similar; the vehicle number provides final clarity.
What was Class 424 built for?
For S-Bahn services in a network whose platforms aren't consistently at S-Bahn height. It was procured for the Hanover area. Where the vehicles are actually deployed today can shift through reallocations and tenders – always check the current picture for up-to-date deployments.
What does 424/434 mean?
These are the two number groups of the same unit. 424 denotes the powered driving cars with a cab, 434 the two intermediate cars. This double-class system applies to almost all German multiple units, including 423/433 or 425/435.
How fast does Class 424 run?
Its maximum speed is 140 km/h. That matches the other S-Bahn vehicles of this generation. In service with closely spaced stops, acceleration out of the stop is the decisive factor anyway.
Why are there four different classes for one design?
Because platform heights and purposes differ. The same basic design produced the 423 for high S-Bahn platforms, the 424 for lower S-Bahn platforms, and the 425 and 426 for regional services. Separate classes make approval, maintenance and operational planning easier.
How do I recognise the family at all?
By three features at once: four car sections (two for the 426), a fully walk-through interior, and Jakobs bogies at the gangways. Plus the characteristic, compactly rounded front shape. Once that combination fits, you're in the family – the vehicle number then settles which class.
What does type code 94 tell you?
It sits at the first two positions of the twelve-digit UIC vehicle number and denotes electric multiple units and railcars. It's independent of whether the vehicle runs S-Bahn or regional services – only the class number makes that distinction.
Is it worth paying attention to platform heights?
Yes, it's one of the underrated identification features. Whether boarding is step-free at floor level or involves steps reveals the vehicle's design – and with it, often, whether you're looking at an S-Bahn or a regional vehicle.
Log your sighting of the Class 424/434
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