British carriage and wagon numbering and classification

A number of different numbering and classification schemes have been used for carriages and wagons on Britain's railways, and this page explains the principal systems. Carriages and wagons (either not self-propelled, or part of a multiple unit which has power units distributed throughout a semi-permanent formation of carriages) have frequently had similar arrangements for classification and numbering, so are considered together.

Source: Wikipedia — British carriage and wagon numbering and classification (CC BY-SA 4.0)