From the introduction of TOPS in 1973, all British Rail diesel and electric locomotives and multiple units were allocated to a particular traction maintenance depot or TMD. Drawing from the terminology of steam traction, these depots were generally referred to as "sheds", and indeed most locations were those which had possessed depots for steam locos. Each TMD had a two-character code which was originally displayed underneath the number of each locomotive allocated there. Later this was extended to cover each carriage of diesel multiple units (DMUs), and even some coaching stock; at this time additional depot codes were added covering places with coaching stock allocations, and also works locations.
Locations given a TOPS code included all TMDs, servicing depots (where minor work such as A exams could be undertaken), and some stabling points (SPs) where locomotives or multiple units would be parked when not required. The locations varied from comprehensively equipped depots, through covered accommodation with fuelling point, to a mere siding. The use of TOPS codes for SPs was somewhat haphazard, with Machynlleth (code MN) hosting one or two locomotives on some weekends while Wolverhampton station, which had no TOPS code, stabled more than a dozen locos.[1]
The application of a depot code was generally reliable as a guide to the base from which the locomotive or multiple unit operated but with some variations, mainly relating to shunters and departmental locomotives.
EMU depots such as Birkenhead North (BD) often required a diesel shunter for moving stock when not powered. As there was no fuelling or maintenance capability at BD, a shunter allocated to nearby Birkenhead Mollington Street (BC) was used, returning to its home depot every four weeks.[2] This arrangement also existed at other locations such as Ilford/Stratford.
Departmental locomotives, by the nature of their use, were sometimes reported as allocated to a base location or even to a region in general rather than an official depot. The Western Region sometimes followed this practice, with number 20 (latterly 97020) reported as allocated to "Reading Signal Works" throughout the 1970s.[3] Locomotives used for research purposes would be reported as allocated to the Derby Research Centre.
| TOPS code | Shed name | Origins | Comments | |
|---|---|---|---|---|
| AB | [4] | |||
| AC | Aberdeen Clayhills | [5] Carriage maintenance depot | ||
| AF | Ashford Chart Leacon | |||
| AK | Manchester Ardwick | [6] | ||
| AL | Aylesbury | [7] | ||
| AN | ||||
| AY | ||||
| BA | Basford Hall (Crewe) | |||
| BB | Beachbrook Farm EWS | |||
| BC | LNWR and GWR joint | |||
| BC | Bicester | |||
| BC | Beachbrook Farm Freightliner | |||
| BD | Wirral Railway | EMU depot,[8] from BN from 1976 | ||
| BE | Bedford Midland Station | No allocation - Fuelling Point only. | ||
| BG | Botanic Gardens (Hull) | |||
| BG | Billingham | |||
| BH | Midland Railway | |||
| BI | Brighton Lovers Walk | EMU depot | ||
| BJ | DMU depot | |||
| BK | Mersey Railway | EMU depot | ||
| BK | Bristol Barton Hill | from 1992 | ||
| BL | ||||
| BL | Basford Hall Freightliner | |||
| BM | Bournemouth | EMU depot | ||
| BN | Birkenhead North | to BD from 1976 | ||
| BN | HST depot, from 1976 | |||
| BP | Beattock | to 1976 | ||
| BP | Carriage maintenance depot | |||
| BQ | EMU depot, from BV from 1975 | |||
| BR | Bristol Bath Road | GWR | ||
| BS | ||||
| BT | Bo'ness | |||
| BU | ||||
| BV | Bury | to BQ from 1975 | ||
| BW | Barrow | |||
| BW | Barry | |||
| BX | DMU depot | |||
| BY | ||||
| BZ | Cornwall Minerals Railway | |||
| CA | Cambridge | DMU depot | ||
| CB | Crewe Basford Hall | |||
| CC | Clacton | EMU depot | ||
| CD | Crewe Diesel Depot | |||
| CE | ||||
| CF | ||||
| CG | Croxley Green | EMU depot, to closure in 1985 | ||
| CG | Crewe Gresty Lane | GWR | ||
| CH | ||||
| CJ | Clapham Junction | No allocation. | ||
| CK | Corkerhill | DMU depot[9] | ||
| CL | Carriage maintenance depot | |||
| CM | Camden | Carriage maintenance depot | ||
| CO | Coquelles (France) | |||
| CP | Crewe Carriage Shed | No allocation - Fuelling Point only. | ||
| CQ | Crewe Heritage Centre | Storage Facility & Heritage Centre | ||
| CR | Colchester | |||
| CS | Carnforth | West Coast Railways | ||
| CV | [10] | |||
| CW | Cricklewood | |||
| CZ | Central Rivers | |||
| DA | DMU depot | |||
| DE | Dewsbury | |||
| DE | Dundee | |||
| DF | Derby Fragonset | |||
| DI | Didcot Railway Centre | |||
| DL | No allocation. | |||
| DM | Dagenham | |||
| DM | Dee Marsh | |||
| DN | ||||
| DR | Doncaster | |||
| DT | ||||
| DY | Derby Etches Park | DMU depot | ||
| EC | HST depot Carriage Maintenance Depot | |||
| ED | ||||
| EG | Edge Hill | |||
| EH | Eastleigh | |||
| EJ | Ebbw Junction (Newport) | |||
| EM | EMU depot | |||
| EN | Carriage maintenance depot | |||
| EU | Euston Station | |||
| EX | ||||
| FB | Ferrybridge | |||
| FF | Brussels Forest (Belgium) | Eurostar depot | ||
| FH | Frodingham (Scunthorpe) | |||
| FP | Finsbury Park | |||
| FR | Fratton (Portsmouth) | EMU depot | ||
| FW | Fort William | |||
| FX | Felixstowe | |||
| GC | Cowlairs (Glasgow) | Carriage maintenance depot | ||
| GD | ||||
| GF | DMU depot | |||
| GI | Gillingham | EMU depot | ||
| GL | Gloucester | |||
| GM | ||||
| GU | Guide Bridge | |||
| GW | Electric locomotive/EMU depot | |||
| GY | Garston Yard | |||
| HA | ||||
| HD | ||||
| HE | EMU depot | |||
| HF | Hereford | |||
| HG | ||||
| HI | Hitchin | |||
| HM | ||||
| HN | DMU depot | |||
| HO | Holbeck (Leeds) | |||
| HQ | BRB Headquarters | Paper allocation | ||
| HR | Hall Road (Liverpool) | EMU depot | ||
| HS | Hammerton Street (Bradford) | |||
| HT | HST and DMU depot | |||
| HY | EMU depot | |||
| IL | Ilford | EMU depot | ||
| IM | ||||
| IP | Ipswich Station | No allocation - Fuelling Point only. | ||
| IS | ||||
| KD | Carlisle Kingmoor | |||
| KK | Kirkdale (Liverpool) | EMU depot | ||
| KM | Carlisle Yard | No allocation - Fuelling Point only. | ||
| KN | MoD Kineton | |||
| KT | MoD Kineton | |||
| KX | No allocation - Fuelling Point only. | |||
| KY | ||||
| LA | Intercity HST, DMU | |||
| LC | Longsight International | Eurostar depot | ||
| LE | ||||
| LG | Electric locomotive and EMU depot | |||
| LJ | ||||
| LL | Liverpool Edge Hill | Carriage maintenance depot | ||
| LM | Long Marston (MoD) | |||
| LN | DMU depot[11] | |||
| LO | ||||
| LP | Le Landy (Paris) | Eurostar depot, to 1994 | ||
| LR | Leicester | |||
| LV | Liverpool Street | No allocation | ||
| LY | Le Landy (Paris) | Eurostar depot, from 1994 | ||
| MA | Manchester Longsight Carriage Maintenance Depot | |||
| MB | Middlesbrough | |||
| MD | Merehead | |||
| ME | Marylebone | DMU depot | ||
| MG | ||||
| MH | ||||
| ML | ||||
| MN | ||||
| MR | ||||
| MV | Carriage maintenance depot | |||
| NA | South Devon Railway | |||
| NC | Carriage maintenance depot | |||
| NG | New Cross Gate | Carriage maintenance depot | ||
| NH | Newton Heath (Manchester) | Lancashire & Yorkshire Railway | DMU depot | |
| NL | Neville Hill (Leeds) | HST and DMU depot | ||
| NT | Nottingham Carriage Sidings | |||
| NM | Northam | |||
| NN | Northampton | |||
| NP | North Pole International | |||
| NR | Norwich | |||
| NW | Northwich | No allocation - Fuelling Point only. | ||
| OC | ||||
| OD | Old Dalby | |||
| OH | Old Oak Common (Heathrow Express) | Heathrow Express EMU depot | ||
| OM | Old Oak Common Carriage Maintenance Depot | |||
| ON | Orpington | EMU depot | ||
| OO | HST depot | |||
| OX | Oxford | |||
| OY | Oxley (Wolverhampton) | Carriage maintenance depot | ||
| PA | St Pancras | No allocation. | ||
| PB | Peterborough | |||
| PC | ||||
| PH | Perth Station | |||
| PI | North Pole International | 1994-1995 | ||
| PM | Bristol St Phillips Marsh | HST depot | ||
| PO | Polmadie (Glasgow) | |||
| PQ | Parkeston Quay | |||
| PZ | Penzance | |||
| RB | Ranelagh Bridge | No allocation - Fuelling Point only. | ||
| RE | Ramsgate | EMU depot. Changed to RM. | ||
| RG | DMU depot | |||
| RL | Ripple Lane | |||
| RM | Ramsgate | EMU depot. Was RE. | ||
| RR | Radyr | |||
| RS | Reddish | |||
| RU | Rugby | |||
| RY | EMU depot | |||
| SA | ||||
| SB | Shirebrook | |||
| SD | Selafield | Direct Rail Services | ||
| SE | St Leonards | DEMU depot | ||
| SF | ||||
| SG | EMU Depot | |||
| SI | ||||
| SL | Electric locomotive and EMU depot | |||
| SN | Stranraer | |||
| SP | Wigan Springs Branch | |||
| SQ | Stockport | |||
| SR | ||||
| ST | Severn Tunnel Junction | |||
| SU | Selhurst | EMU depot | ||
| SV | Wembley Chiltern | |||
| SW | Swindon | |||
| SY | Saltley (Birmingham) | |||
| SZ | Southall | DMU depot[12] | ||
| SZ | Southampton Maritime | Freightliner | ||
| TB | Three Bridges | |||
| TD | Temple Mills | |||
| TE | ||||
| TF | Thornton Fields (Stratford) | Carriage maintenance depot | ||
| TG | Tonbridge | |||
| TI | ||||
| TJ | Thornton Junction | |||
| TL | Tilbury | |||
| TN | Taunton | |||
| TO | ||||
| TP | Trafford Park | |||
| TS | DMU depot | |||
| TW | Tunbridge Wells West Station | DEMU depot | ||
| TY | ||||
| VR | Vale of Rheidol Railway (Aberystwyth) | Steam locomotive depot | ||
| WA | Warrington Arpley | |||
| WB | Willesden Brent Sidings | Carriage maintenance depot | ||
| WC | ||||
| WD | Wimbledon | EMU depot | ||
| WH | Wath | |||
| WH | Whatley | from 1994 | ||
| WJ | Watford Junction | No allocation - Fuelling Point only. | ||
| WK | Workington | |||
| WN | ||||
| WO | Wellingborough | No allocation - Fuelling Point only. | ||
| WS | Worcester | |||
| WT | No allocation - Fuelling Point only. | |||
| WY | Westbury | |||
| YC | York Clifton | |||
| YK | York |
| TOPS code | Works name | Origins | Comments | |
|---|---|---|---|---|
| ZB | Doncaster Works Wabtec | |||
| ZC | ||||
| ZD | Derby Litchurch Lane Works | |||
| ZE | ||||
| ZF | Doncaster Works Bombardier transportation | |||
| ZG | ||||
| ZH | Glasgow Springburn Works | |||
| ZH | ||||
| ZI | Ilford works | Bombardier transportation. | ||
| ZL | ||||
| ZN | ||||
| ZP | Horbury (Wakefield) | Bombardier transportation. |