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. There are also links to other pages that deal in greater depth with the particulars of individual types. Note on classification Carriage and wagon classification has never been quite the same as locomotive and multiple unit classification. For most railways, specific types were identified by their Diagram Number. This could simply be arranged by consecutive number, or there could be some greater organisation of numbers so that similar types were grouped together. However, carriages and wagons have rarely been referred to in general terms by their Diagram Number. Instead there have been a variety of other codes and designations, referring to generic designs rather than specific types. For instance, there were the BR (adapted from the LNER system) and LMS carriage codes, which indicated interior layout or usage. The Great Western Railway (GWR) identified some of their non-passenger carriages and wagons through a series of animal designations, including sea life for departmental (non-revenue earning) stock, followed by a letter for detail differences, e.g. Beetle A. The majority of the sections below deal solely with carriage and wagon numbering series, though where a particular classification system was used this is also described. Pre-nationalisation arrangements Before nationalisation in 1948, each railway company had its own numbering arrangements. The Great Western Railway and London, Midland and Scottish Railway (from 1933) adopted a system which allocated number ranges within a series for different types. The Southern Railway followed a similar approach, but used two series; for passenger carriages and for non-passenger carriages. The London and North Eastern Railway numbered its carriages with the first digit indicating the area it was allocated to. The Great Western Railway Diagram Numbers included a letter to indicate the general layout or usage, followed by a serial number issued consecutively. British Railways British Railways inherited the stock of the 'Big Four' and a substantial number of 'Private Owner' wagons. It also inherited the stock of the Pullman Car Company when it was nationalised in the late 1950s. Numbering system Arrangements at Nationalisation The numbers of carriages and wagons