While traveling Europe, I noticed codes written on trains (public transport as well as cargo), which are written like words but seem to be codes. Examples: Shimms, Shimmns, Tads. Case exactly as written. Dutch and Austrian trains.

When googling, we get pictures of mainly cargo wagons, like it was a particular make or model of something. But no explanation. Are these codes? What information do they convey?

  • 2
    They’re just names of types of wagons.
    – Roy
    Commented Jan 22, 2020 at 7:54
  • 1
    in this case there must be a special pronunciation training for operating staff.
    – dlatikay
    Commented Jan 22, 2020 at 8:02
  • Is this a travel question?
    – gerrit
    Commented Jan 22, 2020 at 16:39
  • 6
    definitely. I need to be able to tell my Shimmns from a Hbillns, when I trainhop. especially during winter.
    – dlatikay
    Commented Jan 22, 2020 at 18:28
  • From the title I expected this about ADR, other cargo placards or UN/NA identification numbers.
    – Mast
    Commented Jan 23, 2020 at 8:53

1 Answer 1


This is a standard classification of railway rolling stock by the UIC (international railway union). Altough it's not adopted worldwide, it is in wide use throughout the EU because it forms a part of the EU Technical Specification for Interoperability (TSI). However, some national deviations still exist.

Although the codes may in some cases look somewhat like real words, they're actually just composed of (groups of) letters, each with a specific meaning. The first (uppercase) letter(s) always denote a general category of the carriage, while the lowercase letters describe its various features (these are not entirely standardized).

See Wikipedia for all the gory details for passengers and freight.

Just a couple of examples of the uppercase letters:

  • A: first class passenger coach
  • B: second class passenger coach
  • E: open high-sided freight wagon
  • S: special flat-bed wagon
  • Z: tank wagon

So for example, "Bmz" would be a second class coach, longer than 24 meters (m), with a central supply of electricity for sockets (z). Your "Simms" is a flat-bed with a fixed front wall and movable top cover (i), loading length < 15 m (mm), capable of up to 100 km/h (s).

  • 3
    Note that in addition to the UIC classification, there may be a national classification as well. For instance in France, ZRAB would be a car that is part of an electric set (Z), that is itself not motorised (i.e. a trailer, R for "remorque"), and has both 1st and 2nd class (A and B). This is usually followed by the series number and the serial number. So a trainset could be ZB + ZRB + ZRAB + ZB for instance.
    – jcaron
    Commented Jan 22, 2020 at 12:53
  • 5
    Though this UIC classification might be "worldwide", I have never seen/heard it used in the USA.
    – Milwrdfan
    Commented Jan 22, 2020 at 16:54
  • 27
    @Milwrdfan, are you surprised that the country that has banking system, measurement system, and medical system incompatible with the rest of the world also classifies train cars differently?
    – WGroleau
    Commented Jan 22, 2020 at 19:43
  • 2
    @Tim there's a lot of compatibility across the EU, including the UK, for the next few days anyway. I crashed my bike in Ireland (I'm British) and apart from needing to show my EHIC to prove I was entitled to it, all the emergency care I needed was as if I was at home. It wasn't complete - I took paper copies of my notes and a CDROM of a CT scan home with me to transfer into the British system, but despite huge NHS IT projects that can still be the case within the UK. Commented Jan 23, 2020 at 9:37
  • 2
    @csk obviously they are primarily used in Europe as we have many small countries that allow for many transit lines over borders (like harbor in Netherlands or Germany, then by train to Switzerland, Austria, Italy, eastern Europe .For this we now use electric locomotives with up to 4 independent current systems including different pantographs. Here the standardization of the waggon-names comes into play because it allows far easier travel over borders:
    – eagle275
    Commented Jan 23, 2020 at 10:50

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