British Rail regional multiple unit numbering
Prior to the introduction of
TOPS,
electric multiple unit numbers were allocated by the
British Rail regions in their own series.
Diesel multiple units did not carry unit numbers at first, but the Scottish and Western Regions later adopted their own series for these units, whilst elsewhere individual depots allocated unit numbers, often prefixed by their two-letter TOPS depot code (e.g. TS for Tyseley).
When TOPS numbers were applied to
multiple units, the original unit numbers were simply prefixed by the class number to make up the required new six-digit unit numbers. These regional series have been perpetuated since TOPS because it eases the description of individual units and avoids potential confusion if there is only one unit with a particular identifier working in a certain area.
Southern Region units are excluded from this page, as they perpetuated the four-digit unit numbering series commenced by the
Southern Railway. For details of the more involved arrangements on the Southern Region, see
SR Multiple Unit Numbering and Classification.
London Midland Region
There was never a regional number series for DMUs in this region, but individual depots did have their own series, prefixed by their two-letter TOPS depot code. The table below shows the series used by Tyseley depot (which was part of the Western Region until 1963).
Scottish Region
The table below shows the braod arrangement of multiple unit numbers in this region, though a couple of Class 104 units also took numbers in the 3xx series. The surviving Class 107 units were later renumbered twice, first to 7xx following the introduction of the
Class 156 units, which had 4xx unit numbers in the Regional Railways Sprinter series, and then to 0xx following the introduction of the
Class 158 units, which had 7xx unit numbers in the Regional Railways Sprinter series.
Western Region
Unit numbers were prefixed by a letter (letters prior to 1970) to indicate which area (or depot) the unit was allocated to. The table below lists the prefixes used; note that Tyseley had transferred to the London Midland Region by the time that the 1971 changes took place so was not included, though it did shorten its prefix to TS.
| Prefix | Area | Depot | | Post-1970 | 1958-1970 |
|---|
| B | BL | Bristol | Bath Road |
| C | CAT | Cardiff | Cathays |
| CDF | Canton |
| L | RDG | London | Reading |
| - | Old Oak Common |
| P | LA | Plymouth | Laira |
| S | - | Swansea | Landore |
| - | TYS | Birmingham | Tyseley |
|
The unit number ranges used were:
Network SouthEast
NSE adopted the former Western Region series, and expanded it to include its other diesel multiple units (those used on the former London Midland Region), which took unit numbers in the 7xx series. This included units from Classes
101,
104,
108 and
117.
Regional Railways
Sprinter (Class 15x) units carried the same last three digits as the last three digits of their carriage numbers in the 52xxx and 57xxx series. The 6xx series was reserved for use by the aborted
Class 157 stock, and so instead was adopted for use by refurbished Class
143 (numbers 601-625) and
101 (numbers 651-695) units. Refurbished Class
117 and
122 units kept their Tyseley 3xx and Laira (Western Region) 1xx unit numbers respectively.
Eastern Region
When first introduced, the Class 306 units were numbered 01-92 and the Class 307 units were numbered 01s-32s. These numbers were amended as they were converted from 1500 V DC to 25 kV AC operation. Parcels & departmental units in the 99x series have included Classes
308/4,
302/9,
316 and
937.
London Midland Region
Scottish Region
