Key takeaways
- The 31WE is a Stadler FLIRT in the regional version for the area around Warsaw.
- Surest feature: Jacobs bogies – count the bogies, there are fewer than car sections.
- The code WE stands for electric railcar under the Polish scheme, with the leading number denoting the type.
- German connection: the FLIRT family is also widespread in Germany, so you already know the basic shape.
- Fleet deployment and numbers change with contract awards and timetable years; check the current situation.
Contents
Fact file
| Vehicle type | Electric articulated multiple unit for regional services |
|---|---|
| Manufacturer | Stadler, FLIRT vehicle family |
| Operator | Koleje Mazowieckie, regional services for the Masovian Voivodeship |
| Construction | Articulated unit with Jacobs bogies between the car sections |
| Boarding | Low-floor section at the entrance, continuous interior |
| Electrification system | 3 kV DC, the standard system on the Polish network |
| Type designation | 31WE under the Polish scheme for electric railcars |
| UIC country code | 51 for Poland |
Identifying features
Is this really the class in front of you?
- Fewer bogies than car sections – the bodies rest jointly on Jacobs bogies
- Continuous interior with no gangway doors between the car sections
- Characteristic FLIRT front with a large, deeply sloped windscreen
- Low boarding step in the middle section of the vehicle
- Pantograph on the roof – a purely electric vehicle
- Markings with the code 31WE and the Koleje Mazowieckie logo
Updated: August 2026 – A modern multiple unit with a deeply sloped windscreen, a continuous interior and a strikingly low bogie count: the 31WE is Stadler’s FLIRT variant for Koleje Mazowieckie, the regional operator around Warsaw. This page shows you how to identify it beyond doubt, what its designation means and what matters when photographing it.
Spotted a multiple unit? Note the number.
Many modern multiple units look alike – the number is what makes your sighting unambiguous.
What is the 31WE?
The 31WE is an electric articulated multiple unit from Stadler’s FLIRT family, procured for Koleje Mazowieckie. This company operates regional services in the Masovian Voivodeship, meaning the area around and the region of the capital, Warsaw. In the city itself, Metro Warszawa adds its own system, separate from the railway network. The vehicle is thus clearly placed: local traffic, short stop spacing, high passenger turnover.
The FLIRT family is one of the most widespread multiple-unit designs in Europe altogether. Anyone who travels regularly in Germany knows the basic shape from numerous operators – and that’s exactly what makes the 31WE a good entry point if you want to get to know Polish rolling stock: the shape is familiar, only the markings and the electrification system are new.
Understanding the Polish type designation
Two naming systems run in parallel in Poland, and both are useful for spotters.
| System | Structure | Example |
|---|---|---|
| PKP class code | traction letter + service letter + number | EN57 = electric local-service multiple unit, ED250 = electric long-distance multiple unit |
| Works and type designation | number + letter code | 31WE – WE stands for the electric railcar |
| Manufacturer product name | manufacturer’s brand | FLIRT (Stadler), Impuls (Newag), Elf (PESA) |
| International number | twelve-digit UIC number | country code 51 for Poland |
This triple naming regularly causes confusion, because the same vehicle can appear under three different names. The rule behind it is simple: the product name describes the vehicle family, the type code the specific design, and the full vehicle number identifies the individual example. How the international number is structured and what the check digit does is explained in the article on reading the UIC number on a vehicle.
The surest way to identify it: count the bogies
Count the car sections
Walk along the platform and count the individual car bodies of the train.
Count the bogies
Now count the bogies. If there are fewer than car sections, you're looking at an articulated unit with Jacobs bogies – the core feature of the FLIRT family.
Look at the gangways
On articulated units, the gangway sits directly above the shared bogie. On classic multiple units, two separate car ends sit next to each other there instead.
Check the markings
31WE plus the Koleje Mazowieckie logo makes the identification certain. Note the full vehicle number at the same time.
This method works right across Europe, and it’s one of the few features you can reliably read even from a moving train. The general methodology behind it – from coarse to fine features – is described in the guide to identifying train classes.
Look at the gangways
If you're unsure whether a train has Jacobs bogies, look at the area between two car sections. A single bogie directly under the bellows is the clear proof.
Operational context and the German connection
Poland’s network is electrified at 3 kV DC, the German one at 15 kV AC. For purely Polish multiple units, that means a hard boundary: they stop at the system boundary unless they were specifically built to run on multiple systems.
| Environment | Chance of a sighting | Why |
|---|---|---|
| Regional hubs around Warsaw | high | the operator’s core territory |
| Larger stations with regional services in Masovia | high | dense service, good platform sightlines |
| Border stations along the Oder and Neisse | low | different operators, different vehicles |
| The German network | very low | different electrification system, different transport contracts |
| Freight hubs and marshalling yards | very low | the wrong vehicle world |
Contract awards change the fleet distribution
Which operator runs which vehicles on which routes depends on transport contracts and tenders. This allocation can shift completely with a timetable change – treat any statement about it as a snapshot.
Which multiple units are running where right now?
Real-time community sightings show you the current fleet distribution – better than any list.
The system changeover at the border explained
For German spotters, the electrification system boundary is the main reason why Polish multiple units practically never turn up in everyday German railway life. Poland electrifies at 3 kV DC, Germany at 15 kV AC at 16.7 hertz. A vehicle built for only one of these systems cannot run on the other network.
That’s exactly why cross-border services are usually organised either with multi-system vehicles, with diesel traction, or with a vehicle change at the border station. Exactly where the system boundaries lie and which stations are reachable from which system depends on the specific infrastructure and changes with expansion projects – you should research that up to date for a planned trip rather than deriving it from a general rule.
In practice, that means: if you want to see Polish regional multiple units, plan a trip to Poland and don’t expect to find them on the German side. Conversely, the border region is still interesting, because different vehicle worlds meet there at short range.
Photo tips for regional multiple units
Multiple units are photographically less rewarding than locomotives: long, uniform side surfaces, little structure, often poor platform light. Four decisions still turn that into a usable shot.
Platform end instead of platform middle
From the end you get a three-quarter view with front and flank instead of a flat side wall.
Emphasise the front
The large, deeply sloped windscreen is the face of the FLIRT family. It belongs in the shot, or the photo becomes generic.
Check the background beforehand
Masts, bins and shelters ruin more platform shots than bad light does. Choose your position accordingly.
Stay on the platform
The track area is not a photo spot. The white line is the boundary, even when no train is coming right now.
The technical basics for sharp train photos – shutter speed, focus, panning – are covered in the guide to good photos of trains. And if you’re unsure whether a vehicle even belongs to local or long-distance services, the article on the difference between local and long-distance services helps.
Common mix-ups
It points to a FLIRT if …
- there are fewer bogies than car sections
- the gangway sits directly above a shared bogie
- the front has a large, deeply sloped windscreen
- 31WE is written on the vehicle
Look more closely if …
- you only see the train from the side and the front is missing
- a special livery changes the appearance
- another operator runs a similar-looking vehicle
It is not a 31WE if …
- every car has two of its own bogies
- a separate locomotive is hauling the train
- the markings name a different operator or a different design
Conclusion
The 31WE is a good example of how modern multiple units are better identified by their construction than by details: the shared bogies make the FLIRT family unmistakable, and the markings provide the confirmation. If you want to keep looking around Poland, the ED160 based on the FLIRT is the long-distance version of the same family, while the Newag Impuls and the PESA Elf are the Polish competition. The classic of Polish local services alongside them remains the EN57.
In brief
Fewer bogies than car sections, a large windscreen, the marking 31WE: that identifies the Koleje Mazowieckie FLIRT beyond doubt. Look for it on regional services around Warsaw – and document it with the full vehicle number.
Collect and compare Polish multiple units
FLIRT, Impuls and Elf look more alike than you'd think – documented sightings keep you on top of it.
Summary
- The 31WE belongs to Stadler's FLIRT family and is used by Koleje Mazowieckie on regional services.
- It is built as an articulated unit: the car sections share bogies, which makes it visually unmistakable.
- Because the Polish network is electrified at 3 kV DC, purely Polish multiple units are tied to this system.
- For identification in the field, the number of bogies, the front shape and the vehicle markings are what count.
Frequently asked questions
What is the 31WE?
An electric articulated multiple unit from Stadler's FLIRT family, procured for Koleje Mazowieckie, the regional operator for the Masovian Voivodeship around Warsaw. It is built for local services, has a continuous interior and rests on Jacobs bogies that are each shared between two car sections.
What does the designation 31WE mean?
Polish railcars carry a type designation of number plus letters alongside their running number. The WE denotes an electric railcar, and the leading number stands for the design. This works designation exists alongside the PKP class codes, which start with E, such as EN57 or ED250.
How do I reliably identify a FLIRT?
By its Jacobs bogies. Count the car sections and the bogies: on a FLIRT there are fewer bogies than bodies, because neighbouring sections share one. Classic multiple units with two bogies per car look markedly different around the gangways.
Do these trains also run into Germany?
The Polish network is electrified at 3 kV DC, the German one at 15 kV AC. Purely DC vehicles therefore stop at the system boundary. Whether and where vehicles change over along the Oder and Neisse depends on the infrastructure and on transport contracts, and it changes.
What sets the 31WE apart from other Polish multiple units?
Above all the articulated construction with shared bogies and the characteristic Stadler front. Polish competitor products such as the Newag Impuls or the PESA Elf are independent designs with different proportions and window layouts.
Is the 31WE a long-distance or local service train?
A local service vehicle. Koleje Mazowieckie operates regional services; the seating, door layout and boarding height are designed for that. For long-distance services Poland uses other vehicles, whose PKP code starts with ED rather than EN.
How do I document a sighting properly?
With the full vehicle number, the date and the location. Every vehicle also carries a twelve-digit UIC number, whose country code for Poland is 51. A second photo of the number saves you every identification argument later on.
Where's the best place to photograph the 31WE?
At platforms with a view of the whole train length and at publicly accessible spots along regional routes around Warsaw. Which diagrams actually run changes with the timetable years – current community sightings are a better basis than older lists.
Log your sighting of the Koleje Mazowieckie Class 31WE (Stadler FLIRT)
Date, location and vehicle number logged in seconds – and visible to the community.
Related classes
PKP IC ED160 (FLIRT)
The PKP IC ED160 is a Stadler FLIRT in Polish long-distance service. The familiar FLIRT silhouette meets the Polish designation system here – here's how to read both.
EMUPKP EN57
The PKP EN57 is Poland's most-built electric multiple unit and has been the face of Polish local services for decades. Here's how to identify it and its many refurbishments.
EMUNewag Impuls (EN76 / EN96)
The Impuls is Newag's electric multiple-unit family from Nowy Sącz. Its product name and PKP class codes such as EN76 or EN96 describe two different levels.
EMUPESA Elf 2
The Elf 2 is the second generation of PESA's multiple-unit family. Because generations look similar from outside, the lettering is what decides identification.
EMUPESA Elf (EN76 / ED78)
The Elf is PESA's electric multiple unit family from Bydgoszcz. Its class codes EN76 and ED78 show how the Polish system encodes use rather than origin.
EMUPESA Swing
The PESA Swing is a low-floor articulated tram from Bydgoszcz. Here's how to recognise it, how to tell it apart from the Twist – and how to photograph it well.
Who is behind it
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Where to see the Koleje Mazowieckie Class 31WE (Stadler FLIRT)
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