Southern Railway multiple unit numbering and classification

The Southern Railway created classification and numbering systems for its large fleet of electric multiple units, perpetuated by the Southern Region of British Rail until the early 1980s, when the impact of TOPS was felt. Some stock is still allocated Southern-style classifications in a semi-official manner.
==Classification:==
The early AC electric multiple units were referred to by a two-letter code. This was adapted for the DC third-rail system that was adopted by the Southern Railway, with units being given a three-letter code (sometimes two letters) prefixed by the number of cars in each unit, e.g. 4SUB for a four-car suburban unit.
The Southern Region perpetuated this, and the same principles were adopted for diesel-electric multiple units but with single-letter codes. The last type to be officially allocated a designation in this series was the PEP stock of the early 1970s. Some types built since have been given semi-official designations in this style.
This is different from the system used by British Rail (adopted from the LNER) to indicate the type of non-powered coach — see British Rail coach type codes.
===AC EMUs:===
SR designation	Meaning
CP 	Crystal Palace
CW 	Coulsdon & Wallington
SL 	South London
===DC EMUs:===
SR designation	BR class	Meaning
GLV 	489 	Gatwick Luggage Van
MLV 	419 	Motor Luggage Van
TLV 	499 	Trailer Luggage Van
2BIL 	401 	Bi-Lavatory
2EPB 	416 	Electro-Pneumatic Brake
2HAL 	402 	Half Lavatory
2HAP 	414 	Half lavatory with electro-Pneumatic Brake
2HIL 	- 	Unit 2611: 2HAL DMBT #10729 paired with 2BIL DTCL #12146
2NOL 	- 	No Lavatory
2PAN 	402 	Parcels and Newspapers
2PEP 	446 	Prototype Electro-Pneumatic Brake
2SAP 	418 	Second-Class Only Hap
2SL 	- 	South London
2WIM 	- 	Wimbledon
3COP 	421 	Coastway Open Plan
3SUB 	- 	Suburban
3TC 	492 	Trailer Control
3TIS 	486 	Vectis (Isle of Wight)
4BEP 	412 	Buffet Electro-Pneumatic Brake
4BIG 	422 	Buffet Brighton
4BUF 	404 	Buffet
4CAP 	413 	Coastway Hap
4CEP 	411 	Corridor Electro-Pneumatic Brake
4CIG 	421 	Corridor Brighton
4COR 	404 	Corridor
4DES 	450 	Desiro
4DD 	- 	Double Deck
4EPB 	415 	Electro-Pneumatic Brake
4GRI 	404 	Griddle Car
4HIT 	455 	HIgh density, Tightlock coupling. Proposed for the class, but not used.
4JOP 	458/0 	Juniper Outersuburban Porterbrook.
4LAV 	- 	Lavatory
4PEP 	445 	Prototype Electro-Pneumatic Brake
4PER 	508 	
4REP 	432 	Restaurant Electro-Pneumatic Brake
4RES 	404 	Restaurant
4SUB 	405 	Suburban
4TC 	438 	Trailer Control
4TEP 	412 	Temporary BEP
4VEC 	485 	Vectis (Isle of Wight)
4VEG 	427 	VEP Gatwick Express
4VEP 	423 	Vestibule Electro-Pneumatic Brake
4VIP 	423 	VEP Intermediate Plan
4VOP 	423 	VEP Open-Plan
5BEL 	403 	Brighton Belle
5DES 	444 	Desiro (Unofficial)
5JUP 	458/5 	Juniper
5TCB 	438 	TC and Buffet
5WES 	442 	Wessex
6CIT 	- 	City Limited
6PAN 	- 	Pantry
6PUL 	- 	Pullman
6REP 	431 	Reformed REP
6TC 	- 	Trailer Control
6JAV 	395 	JAVelin. Unofficial classification, also referred to as 6HIT (Hitachi).
7TC 	- 	Trailer Control
8DIG 	422 	Dedicated Brighton
8GAT 	460 	Gatwick Express
8MIG 	421 	Miniature Buffet and CIG
8VAB 	480 	Vestibule Autobrake Buffet
===Diesel-electric multiple units:===
SR designation	BR class	Meaning
3D 	207 	Oxted
3H 	205 	Hampshire
3R 	206 	Reading
3T 	204 	Hampshire and added Trailer
6B 	203 	Hastings Buffet
6L 	202 	Hastings Long underframe
6S 	201 	Hastings Short underframe
==Unit numbering:==
Unit numbers were allocated from 1001, following the 1–1000 set numbers of semi-fixed formations of hauled coaching stock. Different types of unit were given numbers:
1001–1200	Unpowered trailer units for working with 3SUB stock (this series was later expanded to include 989–1000)
1201–1800	3SUB (ex-LSWR units with 1200 added to their original numbers)
1801–1999	Two-car inner-suburban (e.g. 2NOL)
2001–2899	Two-car outer-suburban (e.g. 2BIL)
2901–2999	Four-car outer-suburban (4LAV)
3001–3999	Four, five and six-car express (e.g. 4COR, 5BEL and 6PUL)
4001–4999	Four-car inner-suburban (4SUB and 4DD)
5001–5599	British Railways four-car inner-suburban (4EPB)
5601–6999	British Railways two-car (e.g. 2HAP)
7001–7999	British Railways four-car outer-suburban (e.g. 4CIG)
8001 	Temporary eight-car (8VAB)
S1–S101 	Departmental (non-revenue earning)
This series was perpetuated by the Southern Region with modifications, as older set numbers were reused for the following different types:
001–099 	Parcels and departmental (Sxxx units renumbered)
301–999 	Trailer control (first digit indicated number of cars, e.g. 301 = 3TC)
1001–1499	Diesel electric multiple units (e.g. 6S)
2PEP reused number 2001, 4REP from 3001 and 4PEP 4001/4002. This series was abandoned in 1983, when units were renumbered to fit in with the TOPS classification system, which had nominally been in use for a decade. Even then, many units displayed only the last four digits, dropping the first two digits – e.g. unit 412 301 would have the number "2301" applied. Only with later units and 2xx series DEMUs were the full numbers shown, e.g. Classes 456, 458/5, 465 and 466, and some Class 455 sets, carry full six-digit numbers.
==See also:==
*List of British Rail classes
*British Rail brand names
Category:Lists
Category:Numbering and Classification
Category:Southern Railway (UK) locomotives