LNER Locomotive Numbering and Classification - Classification - LNER System - Steam Locomotives

Steam Locomotives

When the LNER was created in 1923, a new classification scheme was drawn up that could accommodate all the inherited steam locomotives and future new classes, and provide useful information about the features of a given class. The answer, approved in September 1923, was a variation of the GNR system, using a letter to indicate each type's wheel arrangement (based on the Whyte Notation).

The letters were allocated with passenger engine arrangements first in descending order of coupled wheels ('A' to 'H'), then goods engine arrangements in ascending order of coupled wheels ('J' to 'T'). Letters 'X' to 'Z' were used for a variety of small engine arrangements. Letters 'I' and 'U' to 'W' were left unused at the time, but the latter three were later applied when new wheel arrangements were introduced; I was never used. The full list of letters used was as follows:

The letter 'Z' was initially intended for all miscellaneous classes, including departmental (non-revenue earning types), no matter what their wheel arrangement. However, this application was abandoned in 1927 and the letter was used solely for 0-4-2 types from then onwards.

After the letter was a number, which was unique to a particular class of locomotive. In 1923, these numbers were allocated (with a small number of exceptions) in the following order:

• Tender engines first, then tank engines (except letters 'X' and 'Y')
• Ex-GNR classes first, then ex-GCR, GER, NER (including HBR), NBR and GNoSR classes
• In order of driving wheel diameter, largest first

In order to indicate variations within a class, subclass numbers were issued, taking the form of a suffix to the main class number, e.g. 'D17/1'.

New build and converted locomotives to LNER designs were allocated class numbers in appropriate gaps in the series. On occasions, this led to the re-use of class numbers left vacant following withdrawal or rebuilding of its members. This occurred only infrequently up to 1941, but became more common thereafter. Indeed, on occasions, older classes in the course of withdrawal were reclassified so that new types could have lower numbers; e.g. the old 'B1' class became 'B18' to make room for the new standard LNER 4-6-0 type.

During 1942, three new types were allocated the appropriate letter classification ('A', 'B' and 'D') but without any suffix number; these were prototypes for what were planned to be the new standard LNER classes. However, this approach was not maintained, and the production types were allocated standard class numbers.

It should be noted that a number of classes inherited by the LNER were not formally allocated a place in the new system. Most of these were one-off or departmental engines, or types slated for early withdrawal, although some of the latter survived in stock through to 1928. However, there were some curious gaps in the formal list of class numbers allocated in 1923, and it may be that some of these unused numbers were nominally intended for these classes. Other gaps in the list were clearly left to allow space for the construction of new classes, and many of these gaps were filled in due course.

Engines absorbed from the smaller companies during 1923-1924 (the CV&HR, E&WYUR and MSLR) were either withdrawn before a classification could be allocated or were fitted into appropriate gaps in the class list. For the ex-M&GNJR engines (absorbed 1936), their original single letter classification was maintained through to 1942 when they were, at last, allocated class numbers at the end of the appropriate series. The only exceptions were engines that were identical to ex-GNR designs, which adopted the latters' classification. In contrast, the ex-Metropolitan Railway engines (absorbed 1937) were allocated LNER classifications immediately.