Key takeaways
- The 633 is the three-part PESA Link: a diesel railcar from the Polish manufacturer PESA for German regional services.
- Quickest route to identification: count the car sections, then look at the roof – a radiator instead of a pantograph.
- Telling it apart from the two-part variant comes down purely to the number of car bodies and the vehicle number.
- Service networks and operators change with every contract award – network lists go out of date fast.
- The UIC number begins with 95, the type code for diesel railcars; electric multiple units carry 94.
Contents
Fact file
| Vehicle type | Three-part diesel multiple unit for regional services |
|---|---|
| UIC type code | 95 (diesel railcar / diesel multiple unit) |
| Manufacturer | PESA Bydgoszcz (Poland) |
| Type family | PESA Link – procured in two- and three-part versions in Germany |
| Build | Three car sections with Jacobs bogies between the bodies |
| Typical use | Regional services on non-electrified lines |
Identifying features
Is this really the class in front of you?
- Three car sections in a fixed unit – the two-part sister design has only two
- Short intermediate cars resting on shared Jacobs bogies
- Smooth, modern front end with a large windscreen pulled down low
- Radiator and exhaust packs on the roof instead of a pantograph
- Low-floor entrances in the middle section of the car bodies
- Vehicle number begins with 633, intermediate cars with a leading 9
Updated: August 2026 – A modern low-floor railcar, three car sections, no overhead wire above the track, and radiator packs on the roof: this picture fits Class 633, the three-part PESA Link. This page shows you how to identify the design with confidence, how to tell it apart from the LINT family, and what matters for sightings and photos.
Spotted a 633? Don't forget the number.
With regionally concentrated designs, a documented number makes the difference – done in seconds in Traintrack.
What is Class 633?
Class 633 is the three-part version of the PESA Link, a diesel railcar from the Polish manufacturer PESA Bydgoszcz. The vehicles are built for regional services on non-electrified lines: they generate their own traction power with underfloor diesel engines and need neither overhead wire nor a third rail.
Within the Link family, Germany has procured both two- and three-part versions. The 633 is the longer variant. Operationally it therefore sits in the same niche as the three-part Alstom vehicles of Class 620 (Coradia LINT 81) – the same job, a different manufacturer, a different styling.
How to identify the 633 in the field
Three observations are enough, and they work from some distance too.
Count the car sections
Three bodies in a fixed unit. The middle section is noticeably shorter than the two end cars – a typical picture for segmented railcars with Jacobs bogies.
Look for bogies under the gangways
Only one bogie stands between two car sections. Close-coupled designs such as Class 628 have two there – a difference you can spot instantly from the side.
Look at the roof
Radiator packs and exhaust instead of a pantograph. On modern railcar families this is the decisive feature, because diesel and electric variants often look alike from the side.
If any uncertainty remains, the vehicle number helps: on the powered end cars it begins with 633, unpowered intermediate cars carry the same number with a leading 9. How to read the system behind that is explained in the article on the UIC number on the vehicle; the general sequence for identification is set out in the guide to identifying rolling stock classes.
The two digits that settle everything
The twelve-digit vehicle number begins with 95 on diesel railcars. Electric multiple units carry 94. If you're unsure whether a modern vehicle uses diesel or overhead wire, that's the fastest documented proof.
Where it fits in railway operations
Diesel railcars are gap-fillers in the electrified network: they serve exactly the lines where overhead wire never paid off. For your observation trips that means you need to look specifically for diesel enclaves rather than main lines. One such diesel enclave east of Berlin is also home to the heritage-operated Buckower Kleinbahn.
| Location | Chance of a sighting | Why |
|---|---|---|
| Regional lines without overhead wire | high | Core territory for all diesel railcars |
| Junction stations at the edge of diesel networks | high | Transition from wire to diesel, often with standing time |
| Terminus stations with a turnaround | medium to high | A calm subject, both ends of the train accessible |
| Electrified long-distance lines | low | At best transfer workings |
| S-Bahn networks | very low | Purely electric operations |
Network assignments aren't permanent
Which company serves a diesel network, and with which vehicles, hinges on service contracts with a limited term. Fleets get reassigned, sold on or relivered. So treat older network lists as only a rough guide and check the situation on the day.
Current sightings instead of outdated lists
See in Traintrack which vehicles were last reported where – and plan your trip around it.
Spotting and photography
A three-part low-floor railcar is long, flat and not very textured – without an idea for the shot it quickly turns into a catalogue photo. These points help.
Make the segmentation visible
A slight angled view shows the gangways between the three bodies. That's exactly what makes the design recognisable and sets it apart from two-part vehicles.
Bring the roof into shot
From a slightly elevated, publicly accessible position, the radiator housings become visible – the best argument against confusing it with an electric multiple unit.
Don't crop the markings
The vehicle number on the side wall is the real piece of information. Frame the shot so it stays fully legible.
Safety comes before the angle
Stay behind the platform edge and keep a safe distance. Track areas, operational land and sidings are off limits – even when nothing seems to be running.
Anyone who wants to share the sighting with the community afterwards will find the process in the guide on reporting sightings. Which focal length makes sense for long railcars is covered in the guide to the best telephoto lens for railway photography.
Single-, two- and three-part: why the car count tells you so much
For modern diesel railcars, the number of car sections isn’t a design choice, it’s a capacity decision. Manufacturers offer their platforms in several lengths so that transport authorities can order the right size for every line. That’s why the Link exists in two- and three-part versions in Germany, the LINT family even in four size classes, and the Talent was also built in different configurations.
For identification in the field, that’s a gift. You don’t have to memorise shape details, you just work through a short chain:
- How many car bodies? That narrows the class down within a family.
- How many bogies? Jacobs bogies mean a segmented train, separate bogies mean a close-coupled unit of an older design.
- What’s on the roof? A radiator and exhaust mean diesel, a pantograph means overhead wire.
- How high is the entrance? Step-free means a modern generation, steps mean the previous generation.
Only once these four points are settled is it worth looking at the front-end shape, door layout and window divisions. Kept in this order, identification stays reliable even when a vehicle is running in an unfamiliar livery or the train only passes through briefly.
A second practical point: multi-car railcars often run in double-heading. Two coupled three-part units make a six-part train – anyone who only counts the bodies of the whole train ends up at the wrong class. So watch for the vehicle ends with a driving cab: they mark the boundaries between two units.
Common mix-ups
It points to the 633 if …
- three car sections form a fixed unit
- only one bogie stands between each pair of bodies
- a radiator and exhaust sit on the roof
- the number begins with 633
Look more closely if …
- you only see the vehicle from the side, with no view of the roof
- two short units in double-heading look like one long train
- an unfamiliar livery obscures the styling
- you have to decide between the two- and three-part Link variant
It's not a 633 if …
- a pantograph sits on the roof
- only two car sections are present
- the entrances have steps instead of low-floor access
- the number begins with 620, 622, 623 or 642
The most realistic mix-up is with the Alstom competition: a Coradia LINT 41 of Class 623 is likewise modern, low-floor and diesel-powered, but has two car sections. The two-part Siemens Desiro Classic (Class 642) stands out through its noticeably older styling and front-end shape.
Conclusion
Class 633 is a good example of how modern local-service railcars are identified less by details than by basic features: car count, bogie arrangement, roof fittings. Anyone who works through these three points is almost always right – and the vehicle number provides the proof.
Verdict in brief
Three car sections on Jacobs bogies, radiator packs instead of a pantograph, a number beginning with 633: that's the three-part PESA Link. Everything else – operator, network, livery – is changeable and should be checked on the day.
Collect your diesel railcar sightings systematically
Number, date, location and photo in one place – so you see at once which units you're still missing.
Summary
- Class 633 stands for the three-part version of the PESA Link family in German diesel-powered local services.
- Car count, Jacobs bogies and roof fittings are enough for a reliable identification in the field.
- Because these vehicles belong to a comparatively small design concentrated in a few regions, a targeted sighting takes some planning.
- Operator, livery and service area are changeable and should always be checked against the current situation.
Frequently asked questions
What is Class 633?
Class 633 is the three-part version of the PESA Link, a diesel railcar from the Polish manufacturer PESA Bydgoszcz for German regional services. The vehicles are intended for non-electrified lines and generate their own traction power with underfloor diesel engines.
How do I tell the 633 apart from the two-part variant?
Most simply by the number of car bodies: the 633 has three, the two-part sister design has two. Both share the front-end shape, window band and roof fittings, so they're barely distinguishable up close. The full vehicle number gives the final confirmation.
How do I tell it's a diesel railcar?
By the roof. Instead of a pantograph there are radiator packs and exhaust systems up there. On modern railcars this is the most reliable criterion, because diesel and electric variants of the same vehicle family often look almost identical from the side.
What does the 95 at the start of the vehicle number mean?
The first two digits of the twelve-digit UIC number are the type code. 95 marks diesel railcars and diesel multiple units. A vehicle with 94 would be an electric multiple unit. Reading these two digits already settles the type of traction beyond doubt.
Where does Class 633 run?
On non-electrified regional lines. Which networks that means in practice depends on the service contract currently running and changes with contract terms. So before planning a targeted trip, check the current situation through real-time information and recent sightings rather than older overviews.
Is the 633 related to the LINT family?
Not technically – the LINT vehicles come from Alstom, the Link from PESA. Operationally, both fill the same niche: multi-car low-floor diesel railcars for regional services. That's why you see them in similar settings and can easily mix them up from a distance.
How many car sections does a unit have?
Three. The bodies rest on shared Jacobs bogies, meaning only one bogie stands between two car sections instead of two. That makes the train look more segmented than a close-coupled unit like Class 628.
How do I log a sighting properly?
With the full vehicle number, date, location and livery. For vehicles whose service area is tied to service contracts, the date is especially valuable, because assignments can shift with every change of contract. A side-on photo with legible markings rounds off the entry.
Log your sighting of the Class 633 (PESA Link)
Date, location and vehicle number logged in seconds – and visible to the community.
Related classes
Class 623 (Alstom Coradia LINT 41)
Class 623 is a two-part Coradia LINT 41 – the same build as the older 648, but its own class with its own number range.
DMUClass 620 (Alstom Coradia LINT 81)
The Class 620 is the three-car Coradia LINT 81 – the longest member of the LINT family, and already identifiable by its number of car sections.
DMUClass 642 (Siemens Desiro Classic)
The Class 642 is the Siemens Desiro Classic: two-car, low-floor, with a Jacobs bogie in the middle. Here's how to recognise it reliably and tell it apart cleanly.
DMUClass 668.4
The Class 668.4 is the battery variant of the Siemens Mireo. It runs electrically, charges under overhead line and bridges sections with no contact wire from storage.
DMUClass 670
The Class 670 is a single-unit double-deck diesel railcar from the 1990s – a tiny series that never found a successor in Germany.
DMUClass 672.9 (Bombardier LVT/S)
The Class 672.9 is a light single railcar from Bautzen that continues the branch-line tradition of the East German lightweight railcars.
Who is behind it
Groups, brands, manufacturers and operators – who owns whom and how to recognise them out in the field.
Buckower Kleinbahn
Between Müncheberg and Buckow runs a heritage railway that neither steams nor diesels: the Buckower Kleinbahn runs under overhead wires. Electric vintage railcars on a branch line are a rarity in Germany – a subject you'll hardly find anywhere else.
ManufacturerPESA Bydgoszcz
PESA Bydgoszcz grew out of a railway workshop and is today Poland's best-known rolling-stock builder. Elf, Link, Dart and the tram families shape the picture across the whole country – and with Class 633, a PESA railcar even appears on German vehicle lists.
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