Koleje Dolnośląskie S.A. (KD)

Updated: August 2026 – Polish vehicles don’t carry a plain number, but a small profile: EU07, ET22, SM42, EN57. Two letters, a number – and if you know the key, you immediately know whether a machine is electric or diesel-powered and what it was built for. Koleje Dolnośląskie S.A. is a good occasion to learn this scheme, because both traction types run side by side in regional services.

What is Koleje Dolnośląskie S.A.?

Koleje Dolnośląskie S.A. is a Polish regional passenger rail company. The company name is a pure place name: “Koleje” means railways, “dolnośląskie” is the adjective for the Dolnośląskie voivodeship, in English Lower Silesia. Written out in full, then: Lower Silesian Railways.

This naming pattern recurs across Poland. Several voivodeships run rail companies built the same way – for example Koleje Wielkopolskie for Greater Poland or Koleje Śląskie for Silesia. Such regional companies are typically carried by the respective self-governments and thus sit alongside the nationwide operator Polregio.

The letter key: two characters, two facts

The Polish class scheme works on a principle you can learn in five minutes. The first letter answers the question what powers it, the second what it’s for.

Position	Character	Meaning	Origin
1	E	electric traction	elektryczny
1	S	combustion engine / diesel	spalinowy
2	U	universal, mixed service	uniwersalny
2	T	freight service	towarowy
2	P	passenger service	pasażerski
2	M	shunting duty	manewrowy
–	EN / SA	multiple units: own scheme, not the purpose letter used for locomotives	normalnotorowy

From code to identification in the field

How to systematically identify unfamiliar vehicles when no code is legible is shown in the guide to identifying rolling stock classes.

What to expect in regional services

A voivodeship’s local services cover electrified main lines and non-electrified branch lines at the same time. That’s exactly why you see both traction types there – and can practise the letter key directly.

Type of line	Matching vehicle family	Code start	Feature from outside
electrified, 3 kV DC	electric multiple unit	E…	pantograph, no exhaust
non-electrified	diesel railcar	S…	radiator grille, exhaust system on the roof
mixed, locomotive-hauled	electric locomotive plus passenger coaches	EU… / EP…	locomotive and separate coaches instead of a multiple unit
transfer runs and special workings	varies	varies	formation doesn’t match the regular pattern

Typical representatives from the rolling-stock database are the classic electric multiple unit EN57, the diesel railcar family SA132 / SA133 / SA134, and the universal electric locomotive EU07. A large share of the newer railcars comes from the domestic manufacturer PESA Bydgoszcz. Which type runs on which duty changes with procurement and diagrams – the code on the vehicle stays.

What the number means – and what it doesn’t

After the two letters comes a number. It denotes the type, not the individual vehicle: EU07 means “electric, universal, type 07” – and many machines of this type exist. Which specific example is standing in front of you is only revealed by the attached running number, usually placed right after the type designation.

That means every vehicle carries two independent identifiers. The class designation is the short, meaningful form for everyday use. Alongside it, the data panel carries the twelve-digit European vehicle number, which works independently of language and stays unambiguous even when the national designation no longer tells you anything. How this number is built is explained in the guide to reading the UIC number.

For sightings, a simple rule follows: note both, and note them separately. The class designation tells you at a glance what you saw. The full vehicle number decides whether you’ve caught the same vehicle a second time or a sister vehicle of the same type – a difference that makes an archive either valuable or worthless over the years.

And a warning belongs here too: the number is not a year of manufacture. It was assigned when a type was introduced and says nothing about when a specific example was built, rebuilt or modernised. Modernised vehicles sometimes carry altered designations, sometimes keep the old one. Anyone inferring an age from the number is regularly wrong – much like someone trying to derive a build year from a German class number.

Common mix-ups

• E doesn’t mean “Express”. The first letter names only the traction type.
• S doesn’t mean “S-Bahn”. S stands for the combustion engine, not a type of service.
• Same number, different letter. EU07 and ET22 have nothing to do with each other, even though both start with E.
• A voivodeship railway is not a state railway. Regional companies and the nationwide PKP companies are different businesses.
• Similar names are deceptive. All “Koleje …” companies sound alike – only the adjective names the region.

How to file sightings usefully

A class code without place and time is only half the information. If you’re collecting several voivodeship railways, you also need a clean separation: note the company and the vehicle separately, because vehicles switch between duties but companies don’t. How to keep this up over years is described in the guide to the sightings logbook. And if you’re unsure whether a working even counts as local service, the comparison Local versus long-distance services helps.

In short

The Polish class code is one of the most elegant designation systems in Europe: two letters, two answers, no looking up. With a regional rail company like Koleje Dolnośląskie, you can run through it for both traction types in a single afternoon.