UIC identification marking for tractive stock information

The UIC identification marking for tractive stock is a standard for identifying train stock like locomotives that supply tractive force primarily in Europe. Since the beginning of 2007 locomotives or other traction units in Europe have been given a 12-digit number. Vehicle numbering is now governed by the Intergovernmental Organisation for International Carriage by Rail^[1] and in Technical Specifications for Interoperability (TSI) of the European Union, specifically the European Railway Agency's CR OPE TSI (Conventional Rail OPErations Technical Specification for Interoperability).^[2] This makes the locomotive clearly identifiable within Europe and parts of Asia and northern Africa (see List of UIC country codes).

A complete number is referred to as a European Vehicle Number^[3] and comprises 12 digits as originally outlined in UIC Code of Practice 438-3, Identification marking for tractive stock. Digits 1–2 are the type code, 3–4 the country of origin (where the vehicle is registered), 5–11 are defined by the country concerned, 12 is the check digit calculated via the Luhn algorithm.^[4] It is followed by abbreviations for the country of origin and the owner of the vehicle.

The EU CR OPE TSI required that by 1 August 2008 all traction units had to be registered and marked with their number. Existing locomotive numbers used internally were not necessarily affected, but meanwhile in many countries the vehicles got 12-digit numbers.