Key takeaways
- The PESA LINK is a diesel railcar for non-electrified regional lines, built by PESA in Bydgoszcz.
- It also runs in Germany – there the vehicle family carries the class designation 633.
- Fastest way to recognise it: no pantograph, multiple sections, modern low-floor railcar.
- "LINK" is a product name, not an official designation – that appears on the vehicle and varies by country.
- In Poland, diesel railcars run under SA designations: S for diesel traction, A for the railbus.
Contents
Fact file
| Vehicle type | Diesel railcar for regional services |
|---|---|
| Manufacturer | PESA Bydgoszcz (Poland) |
| Product name | "LINK" – the manufacturer's product designation |
| Construction | Multi-section railcar with a low-floor section |
| Traction | Diesel engines – no overhead line required |
| German designation | Classified in Germany as Class 633 |
| Typical use | Regional services on non-electrified lines |
Identifying features
Is this really the class in front of you?
- No pantograph on the roof – a diesel vehicle, often with visible cooling equipment
- Multi-section railcar with bellows gangways between the car bodies
- Lowered low-floor section around the middle doors
- Modern, widely glazed front with a large windscreen
- Lettering varies by country: SA series in Poland, Class 633 in Germany
Updated: August 2026 – A modern, multi-section railcar with no pantograph on a line with no overhead line at all: that’s the typical setting for a PESA LINK. What’s notable is that this Polish vehicle also runs in regular service in Germany – carrying an entirely different designation there. This page shows you how to recognise it, and how the two designation worlds relate to each other.
Spotted a railcar? Note the operator too.
With vehicle families running in several countries, only the operator makes a sighting unambiguous.
What is the PESA LINK?
The PESA LINK is a multi-section diesel railcar for regional services, developed and built by the Polish manufacturer PESA in Bydgoszcz. It’s designed for lines with no overhead line and generates its own traction power on board – so instead of a pantograph, it runs on diesel engines.
“LINK” here is a product name from the manufacturer, comparable to FLIRT at Stadler or Impuls at Newag. The vehicle itself carries the official designation of the relevant country. In Germany, that’s Class 633 – which puts the LINK among the few Polish railcars that German railfans can encounter day to day without having to cross the border.
Two countries, two designation systems
This is exactly where the LINK becomes a textbook case. The same vehicle family carries completely different designations on either side of the border, because both countries maintain their own systems.
| System | Structure | Examples | What it tells you |
|---|---|---|---|
| Poland (PKP) | Letter for traction + letter for use + digits | SA134, EN57, EU07, ET22 | Traction type and purpose readable directly |
| Germany | Purely numeric class | 633, 648, 622 | Vehicle category only inferable with prior knowledge |
| European (UIC) | Twelve-digit vehicle number with country code | Country code 51 = Poland, 80 = Germany | Unique identity of the individual vehicle |
The Polish scheme is remarkably transparent: the first letter stands for the traction type – E for electric, S for diesel – and the second for the use: U universal, T freight, P passenger train, M shunting service, N railcar. For diesel railcars, the code SA has also become established, where the A refers to the railbus. That’s how the series SA132 to SA134 and SA135 to SA139 came about.
How the European-standard vehicle number that also appears on every vehicle is structured is explained in the article on reading the UIC number and its check digit.
For practical purposes, this gives a simple rule: always note which system you read a designation in. An entry of “633” without context becomes ambiguous as soon as you’re collecting vehicles from several countries – and an entry with an SA series but no operator says little later about where the sighting took place. Country, designation and operator therefore belong together in one record.
This matters all the more because the same vehicle family can be fitted out differently in different countries. Train protection, door control, seating and interior layout are set to the customer’s requirements. Two vehicles of the same basic type can therefore differ significantly in service, even though they look almost identical from the outside – a point that’s regularly underestimated with internationally deployed platforms.
How to identify the LINK in the field
Check the roof
No pantograph, but radiator and exhaust equipment instead: that's a diesel vehicle. That immediately rules out all electric multiple units.
Count the sections
Count the car bodies and the bellows gangways between them. The LINK was built in several lengths – so the number of sections is an important distinguishing feature within the family.
Look at the entrance area
A lowered low-floor section between higher-lying end sections is typical of modern diesel railcars with the drivetrain beneath the floor.
Read the lettering and the operator
The designation tells you which system you're in: SA series in Poland, Class 633 in Germany. The operator adds further context.
Practical tip: the overhead line as a pre-filter
If there's no overhead line at all above the track, you're automatically looking at a diesel or battery vehicle. That single glance upward rules out more possibilities in identification than any detail on the front end.
Collecting across borders
The same type in two countries – keep both sightings recorded separately, with designation and operator.
Context within rail operations
Diesel railcars open up exactly the lines for which electrification never paid off: branch lines, cross-country connections, less densely populated areas. That directly tells you where to find them.
| Location | Chance of a sighting | Why |
|---|---|---|
| Non-electrified regional lines | high | The actual deployment area for this vehicle category |
| Terminal stations of branch lines | high | Long turnaround times, quiet setting, good light |
| Junction stations with a branch line connection | medium | Diesel and electric vehicles side by side in one shot |
| Electrified main lines | low | Mostly electric vehicles run there instead |
| Depots and stabling sidings | none | Operational railway land – no access, no subject |
Deployment areas are subject to change
Which operator runs which vehicles on which network is decided by tenders and transport contracts. These allocations shift – sometimes over a multi-year cycle, sometimes at short notice through fleet swaps. Always check the current situation before a targeted trip.
Photography tips for diesel railcars
Branch lines instead of main lines
Branch lines give you clear, publicly accessible spots with an open view – without overhead line masts cutting across your composition.
Use the missing overhead line to your advantage
Without a contact wire, the sky stays clear. That allows compositions that simply aren't possible on electrified lines.
Watch for exhaust plumes
A visible exhaust plume can appear when the train sets off. Whether that belongs in the shot or not is a matter of taste – but you should plan for it either way.
Keep a safe distance
Only photograph from publicly accessible paths and platforms. Track areas, level crossings and operational railway land are not a place to shoot from.
How to bring together your position, the light and the shutter speed is covered in the guide on taking good photos of trains. Anyone wanting to build a general method for identifying unfamiliar vehicles will find it in the guide to identifying classes.
Common mix-ups
It points to a PESA LINK if …
- there's no pantograph on the roof
- the railcar is multi-section with a low-floor section
- the lettering shows an SA series or Class 633
- the line has no overhead line
Look more closely if …
- the vehicle looks modern but could come from a different manufacturer
- an unfamiliar operator livery obscures the shape
- you only see the rear end or a partial view
It's not a LINK if …
- there's a pantograph on the roof
- a locomotive is hauling coaches instead of a railcar
- the body is boxy and consistently high-floor
Conclusion
The PESA LINK is one of the few vehicles that shows the coexistence of European designation systems in everyday life: an SA series in Poland, Class 633 in Germany, but technically the same family. For identification, a glance at the roof and the number of sections is enough; for a clean sighting, the designation, number and operator all belong together. Anyone who keeps these apart can correctly place vehicles across borders.
In short
No pantograph, multiple sections, modern low-floor railcar: that's the PESA LINK. The designation on the vehicle tells you which country and which system you're currently looking at.
An archive that crosses borders
Designation, operator, location and date in one entry – so even a near-border sighting stays unambiguous.
Summary
- The PESA LINK bridges two worlds: Polish vehicle development and German regional services, where it runs as Class 633.
- It can be recognised by the combination of diesel traction, multiple sections and a modern low-floor design.
- Designations differ by country – the same type carries different numbers on either side of the border.
- Operators and deployment areas change with contract awards; check the current situation before any targeted photo trip.
Frequently asked questions
What is the PESA LINK?
The LINK is a multi-section diesel railcar from the Polish manufacturer PESA in Bydgoszcz, built for regional services on non-electrified lines. It has no pantograph and generates its own traction power on board. "LINK" is the manufacturer's product name, not an official vehicle designation.
Does the PESA LINK also run in Germany?
Yes. The vehicle family is classified in Germany as Class 633, making the LINK one of the few Polish railcars in regular service in Germany. Which operators run the vehicles on which networks does, however, change with contract awards and timetable years.
How do I tell a diesel railcar from an electric multiple unit?
By the roof. An electric vehicle needs at least one pantograph; if there isn't one, it's not a pure electric vehicle. Diesel railcars, on the other hand, often have visible radiator and exhaust equipment. A further clue: they also run where there's no overhead line at all.
What do the Polish SA designations mean?
In the PKP system, the first letter names the traction type: S stands for diesel, E for electric. The second letter describes the use – for diesel railcars, A has become established for the railbus, alongside N for railcars, M for shunting, T for freight and U for universal vehicles.
Why does the same vehicle have different numbers in Poland and Germany?
Because each country maintains its own designation system. Poland uses letter-and-digit combinations such as SA134 or EN57, Germany uses purely numeric classes such as 633 or 648. The only common thread is the European-standard vehicle number, which appears on the vehicle on both sides of the border.
Is the LINK a low-floor vehicle?
It's a vehicle with a low-floor section, meaning part of the interior sits low and is step-free, while the areas above the drive bogies sit higher. This is common in diesel railcars, because the engine and drivetrain need space beneath the floor.
Where do I have the best chance of finding a PESA LINK?
On non-electrified regional lines – in Poland as well as on the German networks where Class 633 is used. Under continuous overhead line on main lines, the chances are low, since electric vehicles generally run there instead.
What should I note down for a railcar sighting?
The full vehicle designation for the relevant country, the running number, date, location and operator. Especially with vehicle families that run in several countries, the operator is important additional information – without it, it's hard to reconstruct later in what context the sighting took place.
Log your sighting of the PESA LINK
Date, location and vehicle number logged in seconds – and visible to the community.
Related classes
PKP SA132 / SA133 / SA134
SA132, SA133 and SA134 are Polish diesel railcars from PESA's range. This page explains the SA designation system and how to identify them in the field.
DMUPKP SA135 / SA136 / SA139
SA135, SA136 and SA139 come from two different manufacturers and share a number block. Why that's the case and how to identify them reliably anyway.
DMUClass 633 (PESA Link)
Class 633 is the three-part PESA Link in German diesel-powered local services. Here's how to recognise it by car count, front-end shape and roof – and tell it apart from the LINT family.
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