Prior to the introduction of TOPS

TOPS

Total Operations Processing System, or TOPS, is a computer system for managing the locomotives and rolling stock owned by a rail system...

, electric multiple unit

Electric multiple unit

An electric multiple unit or EMU is a multiple unit train consisting of self-propelled carriages, using electricity as the motive power. An EMU requires no separate locomotive, as electric traction motors are incorporated within one or a number of the carriages...

 numbers were allocated by the British Rail

British Rail

British Railways , which from 1965 traded as British Rail, was the operator of most of the rail transport in Great Britain between 1948 and 1997. It was formed from the nationalisation of the "Big Four" British railway companies and lasted until the gradual privatisation of British Rail, in stages...

 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 unit

Multiple unit

The term multiple unit or MU is used to describe a self-propelled carriages capable of coupling with other units of the same or similar type and still being controlled from one driving cab. The term is commonly used to denote passenger trainsets consisting of more than one carriage...

s, 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

SR multiple unit numbering and classification

The Southern Railway created classification and numbering systems for its large fleet of electric multiple units that were perpetuated by the Southern Region of British Rail until the early 1980s, when the impact of TOPS was felt...

.

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).

Range	Classes
003-005	Class 128 British Rail Class 128 British Rail Class 128 was a class of diesel multiple unit, built for British Rail. Introduced in 1959, ten of the class were built by Gloucester Railway Carriage and Wagon Company, each with two 230 hp British United Traction engines. The class was built specifically for parcels, fitted out with...
012-014 / 050-062	Class 122 British Rail Class 122 The British Rail Class 122 diesel mechanical multiple units were built by Gloucester RC&W in 1958. Twenty single-car driving motor vehicles, called "Bubble Cars", were built, numbered 55000–55019...
021-027	Class 114 British Rail Class 114 The British Rail Class 114 diesel multiple units were built by BR Derby from 1956 to 1957. Forty-nine 2-car units were built, numbered 50001-49 for driving motors and 56001-49 for driving trailers . The units were used in the early days out of Lincoln TMD on services all over the county...
301-315	Class 117 British Rail Class 117 The British Rail Class 117 diesel multiple units were built by Pressed Steel from 1959 to 1961.When first introduced, these three-car units were all based with the similar Class 121 single carriage units on British Railway's Western Region for suburban work out of London Paddington, as well as...
316-318	Class 118 British Rail Class 118 The British Rail Class 118 diesel multiple units were built by the Birmingham Railway Carriage & Wagon Company and introduced from 1960....
319-342	Class 116 British Rail Class 116 The British Rail Class 116 diesel multiple units were built by BR Derby from 1957 to 1961.-Regular use:These units stayed in regular service until 1990, when they began to be withdrawn from traffic. They were replaced on regional services by the new "Sprinter" derivative units, or by Class 323...  (Replaced 5xx/6xx Series)
401-421	Class 115 British Rail Class 115 The British Rail Class 115 diesel multiple units were 41 high density sets which operated the outer-suburban services from Marylebone usually to destinations such as High Wycombe, Aylesbury and Banbury which are on the Chiltern Main Line and Great Central Main Line...
501-545	Class 116 British Rail Class 116 The British Rail Class 116 diesel multiple units were built by BR Derby from 1957 to 1961.-Regular use:These units stayed in regular service until 1990, when they began to be withdrawn from traffic. They were replaced on regional services by the new "Sprinter" derivative units, or by Class 323...  (Non-gangwayed)
600-629	Class 116 British Rail Class 116 The British Rail Class 116 diesel multiple units were built by BR Derby from 1957 to 1961.-Regular use:These units stayed in regular service until 1990, when they began to be withdrawn from traffic. They were replaced on regional services by the new "Sprinter" derivative units, or by Class 323...  (Gangwayed)

Scottish Region

The table below shows the broad 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

British Rail Class 156

The British Rail Class 156 Super Sprinter is a diesel multiple-unit train . 114 of these units were built from 1987 to 1989 by Metro-Cammell at its Washwood Heath Works in Birmingham...

 units, which had 4xx unit numbers in the Regional Railways Sprinter series, and then to 0xx following the introduction of the Class 158

British Rail Class 158

British Rail Class 158 Express Sprinter is a diesel multiple-unit train, built for British Rail between 1989 and 1992 by BREL at its Derby Works. They were built to replace many locomotive-hauled passenger trains, and allowed cascading of existing Sprinter units to replace elderly 'heritage' DMUs...

 units, which had 7xx unit numbers in the Regional Railways Sprinter series.

Range	Classes
301-366	Class 101 British Rail Class 101 The British Rail Class 101 diesel multiple units were built by Metro-Cammell at Washwood Heath in Birmingham from 1956 to 1959, following construction of a series of prototype units. This class proved to be the most successful and longest-lived of all BR's First Generation DMUs, with the final five...
385-396	Class 116 British Rail Class 116 The British Rail Class 116 diesel multiple units were built by BR Derby from 1957 to 1961.-Regular use:These units stayed in regular service until 1990, when they began to be withdrawn from traffic. They were replaced on regional services by the new "Sprinter" derivative units, or by Class 323...
425-449	Class 107 British Rail Class 107 The British Rail Class 107 diesel multiple units were built by the Derby Works of British Railways and were introduced in 1960. The class looked similar to the later Class 108 units, but were heavier - having been built out of steel.-Usage:...
450-453	Class 104 British Rail Class 104 The British Rail Class 104 diesel multiple units were built by Birmingham Railway Carriage and Wagon Company from 1957 to 1959.The first units ordered were for the London Midland Region, with the majority of the class for use in North West of England with sets also in Tyneside...
501-517	Class 120 British Rail Class 120 The Class 120, were a cross-country DMU in three-car formation, built at the British Rail Swindon Works.Totalling 194 cars, three batches were built:*1958 - 49 sets for the Western Region*1959 - 7 sets for the Scottish Region...

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:

Range	Classes
100-119	Class 122 British Rail Class 122 The British Rail Class 122 diesel mechanical multiple units were built by Gloucester RC&W in 1958. Twenty single-car driving motor vehicles, called "Bubble Cars", were built, numbered 55000–55019...  (Driving Motor 55000-019)
120-135	Class 121 British Rail Class 121 Sixteen Class 121 single-car driving motor vehicles were built from 1960, numbered 55020–55035. These were supplemented by ten trailer vehicles, numbered 56280–56289 . They had a top speed of 70 mph, with slam-doors, and vacuum brakes...  (Driving Motor 55020-035)
200-225	Class 101 British Rail Class 101 The British Rail Class 101 diesel multiple units were built by Metro-Cammell at Washwood Heath in Birmingham from 1956 to 1959, following construction of a series of prototype units. This class proved to be the most successful and longest-lived of all BR's First Generation DMUs, with the final five...  (Motor + Trailer Units)
280-289	Class 121 British Rail Class 121 Sixteen Class 121 single-car driving motor vehicles were built from 1960, numbered 55020–55035. These were supplemented by ten trailer vehicles, numbered 56280–56289 . They had a top speed of 70 mph, with slam-doors, and vacuum brakes...  (Driving Trailer 56280-289)
290-299	Class 122 British Rail Class 122 The British Rail Class 122 diesel mechanical multiple units were built by Gloucester RC&W in 1958. Twenty single-car driving motor vehicles, called "Bubble Cars", were built, numbered 55000–55019...  (Driving Trailer 56291-299)
300-395	Class 116 British Rail Class 116 The British Rail Class 116 diesel multiple units were built by BR Derby from 1957 to 1961.-Regular use:These units stayed in regular service until 1990, when they began to be withdrawn from traffic. They were replaced on regional services by the new "Sprinter" derivative units, or by Class 323...
400-450	Class 117 British Rail Class 117 The British Rail Class 117 diesel multiple units were built by Pressed Steel from 1959 to 1961.When first introduced, these three-car units were all based with the similar Class 121 single carriage units on British Railway's Western Region for suburban work out of London Paddington, as well as...
460-480	Class 118 British Rail Class 118 The British Rail Class 118 diesel multiple units were built by the Birmingham Railway Carriage & Wagon Company and introduced from 1960....
571-596	Class 119 British Rail Class 119 The British Rail Class 119 DMUs were used throughout the Western Region and on services in the Midlands sourced by Tyseley Depot. Shortly after their introduction, sets were transferred from Cardiff to serve the intermediate stations on outer suburban services from London Paddington to Oxford...
600-616	Class 120 British Rail Class 120 The Class 120, were a cross-country DMU in three-car formation, built at the British Rail Swindon Works.Totalling 194 cars, three batches were built:*1958 - 49 sets for the Western Region*1959 - 7 sets for the Scottish Region...
700-7xx	Class 123 British Rail Class 123 The Class 123 was a design of Diesel Multiple Unit built for British Rail in 1963. They were built by British Rail at Swindon Works, and designed like all Swindon units as inter-city sets. Ten of the four-car sets were built and introduced in 1963...
800-874	Class 101 British Rail Class 101 The British Rail Class 101 diesel multiple units were built by Metro-Cammell at Washwood Heath in Birmingham from 1956 to 1959, following construction of a series of prototype units. This class proved to be the most successful and longest-lived of all BR's First Generation DMUs, with the final five...  (Power Twin and 3-Car Units)
900-995	Class 108 British Rail Class 108 The British Rail Class 108 diesel multiple units were built by BR Derby from 1958 to 1961, with a final production quantity of 333 vehicles....

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

British Rail Class 101

The British Rail Class 101 diesel multiple units were built by Metro-Cammell at Washwood Heath in Birmingham from 1956 to 1959, following construction of a series of prototype units. This class proved to be the most successful and longest-lived of all BR's First Generation DMUs, with the final five...

, 104

British Rail Class 104

The British Rail Class 104 diesel multiple units were built by Birmingham Railway Carriage and Wagon Company from 1957 to 1959.The first units ordered were for the London Midland Region, with the majority of the class for use in North West of England with sets also in Tyneside...

, 108

British Rail Class 108

The British Rail Class 108 diesel multiple units were built by BR Derby from 1958 to 1961, with a final production quantity of 333 vehicles....

 and 117

British Rail Class 117

The British Rail Class 117 diesel multiple units were built by Pressed Steel from 1959 to 1961.When first introduced, these three-car units were all based with the similar Class 121 single carriage units on British Railway's Western Region for suburban work out of London Paddington, as well as...

.

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

British Rail Class 157

Class 157 was the designation applied to a range of Diesel multiple unit trains of the Sprinter family planned for regional use, in particular for the Strathclyde Passenger Transport Executive...

 stock, and so instead was adopted for use by refurbished Class 143

British Rail Class 143

The British Rail Class 143 is a diesel multiple unit, part of the Pacer family of trains introduced between 1985 and 1986. They originally worked in the North-East of England but were later transferred to Wales and South-West England....

 (numbers 601-625) and 101

British Rail Class 101

The British Rail Class 101 diesel multiple units were built by Metro-Cammell at Washwood Heath in Birmingham from 1956 to 1959, following construction of a series of prototype units. This class proved to be the most successful and longest-lived of all BR's First Generation DMUs, with the final five...

 (numbers 651-695) units. Refurbished Class 117

British Rail Class 117

The British Rail Class 117 diesel multiple units were built by Pressed Steel from 1959 to 1961.When first introduced, these three-car units were all based with the similar Class 121 single carriage units on British Railway's Western Region for suburban work out of London Paddington, as well as...

 and 122

British Rail Class 122

The British Rail Class 122 diesel mechanical multiple units were built by Gloucester RC&W in 1958. Twenty single-car driving motor vehicles, called "Bubble Cars", were built, numbered 55000–55019...

 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

British Rail Class 308

The British Rail Class 308 alternating current electric multiple units were built by BR at York, in three batches, from 1959–61. They were initially classified as AM8 units before the introduction of TOPS.-Class 308/1:...

, 302/9

British Rail Class 302

The British Rail Class 302 was a type of electric multiple unit introduced between 1958 - 1960 for outer suburban passenger services on the London, Tilbury and Southend Railway route...

, 316 and 937

British Rail Class 937

The British Rail Class 937 was reserved for former AC electrical multiple units, converted for departmental use. Units were converted for various tasks, including application of sandite, and use as tractor units to tow other trains....

.

First Use		Second Use
Range	Class	Range	Class
001-092	Class 306 British Rail Class 306 The British Rail Class 306 was a type of electric multiple unit introduced in 1949. It consisted of 92 three-car trains which were used on newly electrified suburban lines between and London Liverpool Street.- Overview :...
101-132	Class 307 British Rail Class 307 The British Rail Class 307 electric multiple units were built by BR at Eastleigh Works from 1954-1956. They were initially classified as AM7 before the introduction of TOPS.-Description:...	101-121	Class 360/1 British Rail Class 360 The British Rail Class 360 electric multiple units were built by Siemens in two sub-types from 2002-2003 and 2004-2005. These units are part of the Siemens Desiro family.The Siemens "Desiro UK" family also includes units of Classes 185, 350, 380, 444 and 450....
133-165	Class 308/1 British Rail Class 308 The British Rail Class 308 alternating current electric multiple units were built by BR at York, in three batches, from 1959–61. They were initially classified as AM8 units before the introduction of TOPS.-Class 308/1:...
201-312	Class 302/0 British Rail Class 302 The British Rail Class 302 was a type of electric multiple unit introduced between 1958 - 1960 for outer suburban passenger services on the London, Tilbury and Southend Railway route...	301-366	Class 321/3 British Rail Class 321 The British Rail Class 321 alternating current electric multiple units were built by BREL York in three batches from 1988-91. The design was successful and led to the development of the similar Class 320 and Class 322 units for use by Strathclyde PTE and Stansted Express respectively...
313-321	Class 308/2 British Rail Class 308 The British Rail Class 308 alternating current electric multiple units were built by BR at York, in three batches, from 1959–61. They were initially classified as AM8 units before the introduction of TOPS.-Class 308/1:...
401-452	Class 305/1 British Rail Class 305 The British Rail Class 305 was an alternating current electric multiple unit . Under the pre-1973 British Rail numbering system, the class was known as AM5...
453-455	Class 308/3 British Rail Class 308 The British Rail Class 308 alternating current electric multiple units were built by BR at York, in three batches, from 1959–61. They were initially classified as AM8 units before the introduction of TOPS.-Class 308/1:...
481-485	Class 322 British Rail Class 322 The British Rail Class 322 electric multiple units were built by BREL in 1990. Five 4-car units were built for the dedicated Stansted Express service from London Liverpool Street to Stansted Airport. The units were then used by First ScotRail, operating on the North Berwick Branch Line, between /...
501-519	Class 305/2 British Rail Class 305 The British Rail Class 305 was an alternating current electric multiple unit . Under the pre-1973 British Rail numbering system, the class was known as AM5...
601-627	Class 309 British Rail Class 309 The British Rail Class 309 "Clacton Express" electric multiple units were built by British Rail York Works from 1962-1963. They were initially classified as Class AM9 before the introduction of TOPS...
701-799	Class 312 British Rail Class 312 The British Rail Class 312 is a type of alternating current electric multiple unit built in 1975-1978 for use on outer-suburban passenger services. It was the last class of multiple unit to be constructed with the British Rail Mark 2 bodyshell, and also the last with slam doors...
801-861	Class 315 British Rail Class 315 British Rail Class 315 alternating current electric multiple units were built by BREL at York works from 1980 to 1981. They were the fifth and final variety of British Rail's then-standard 1972 design for suburban EMUs, which eventually encompassed 755 vehicles and five Classes...
990-999	Parcels & Departmental

London Midland Region

First Use		Second Use
Range	Class	Range	Class
001-045	Class 304 British Rail Class 304 The British Rail Class 304 electric multiple units were built for suburban use on the first phases of the West Coast Main Line electrification between Crewe and Manchester/Liverpool/Rugby. Originally classed as AM4 units, they later became Class 304 under the TOPS numbering system, and could be...
046-095	Class 310/0 British Rail Class 310 The British Rail Class 310 is a slam-door, alternating current electric multiple unit introduced in 1963 as part of the West Coast Main Line electrification project. They were initially classified as Class AM10 units before the introduction of the TOPS classification system. Constructed at BR's...
101-113	Class 310/1 British Rail Class 310 The British Rail Class 310 is a slam-door, alternating current electric multiple unit introduced in 1963 as part of the West Coast Main Line electrification project. They were initially classified as Class AM10 units before the introduction of the TOPS classification system. Constructed at BR's...
133-189	Class 501 British Rail Class 501 The British Rail Class 501 electric multiple units were built in 1957/58 for use on the former LNWR/LMS suburban electric network of the London Midland Region...
201-204	Class 312/2 British Rail Class 312 The British Rail Class 312 is a type of alternating current electric multiple unit built in 1975-1978 for use on outer-suburban passenger services. It was the last class of multiple unit to be constructed with the British Rail Mark 2 bodyshell, and also the last with slam doors...	201-243	Class 323 British Rail Class 323 The British Rail Class 323 electric multiple units were built by Hunslet TPL from 1992-93. Forty-three 3-car units were built for inner-suburban services around Birmingham and Manchester...
301-348	Class 317/1 British Rail Class 317 The British Rail Class 317 alternating current electric multiple units were built by BREL York in two batches, from 1981-82 and 1985-87. They were the first of several classes of British Rail EMU to be based on the all-steel Mark 3 bodyshell, departing from the "PEP"-aluminium design which had...
401-448	Class 321/4 British Rail Class 321 The British Rail Class 321 alternating current electric multiple units were built by BREL York in three batches from 1988-91. The design was successful and led to the development of the similar Class 320 and Class 322 units for use by Strathclyde PTE and Stansted Express respectively...

Scottish Region

First Use		Second Use
Range	Class	Range	Class
001-091	Class 303 British Rail Class 303 The British Rail Class 303 electric multiple units, also known as "Blue Train" units, were introduced in 1960 for the electrification of the North Clyde and the Cathcart Circle lines in Strathclyde...	001-040	Class 334 British Rail Class 334 The British Rail Class 334 is a suburban electric multiple unit built by Alstom in Birmingham. They are part of the Juniper family of trains along with Classes 458 and 460. They were built for SPT/ScotRail outer suburban services in Glasgow, UK. They later became part of First ScotRail/SPT fleet...
092-110	Class 311 British Rail Class 311 The British Rail Class 311 alternating current electric multiple units were built by Cravens at Sheffield in 1967. They were intended for use on the line from to and , which was electrified in 1967.-Appearance:...
201-216	Class 314 British Rail Class 314 British Rail Class 314 alternating current electric multiple units were built by BREL at York works in 1979. They were the third variety of British Rail's then-standard 1972 design for suburban EMUs, which eventually encompassed 755 vehicles and five classes...
250-270	Class 318 British Rail Class 318 The British Rail Class 318 is an electric multiple unit train, which operates exclusively in the Strathclyde Partnership for Transport network in West Central Scotland. The units were introduced fully on 29 September 1986 as part of the electrification of the Ayrshire Coast Line between and...
301-322	Class 320 British Rail Class 320 The British Rail Class 320 is an alternating current electric multiple unit train found on the Strathclyde Partnership for Transport rail network in Central Scotland, and is used exclusively on the North Clyde Line between Helensburgh and Airdrie, North Lanarkshire via Glasgow Queen Street...