Section codes for overhead line electrification (OLE) installations

A (one day) comprehensive listing

Last update 13 November 2008

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Phil Deaves, Swindon, Wiltshire

I am always grateful for additional information, whether entirely new records (particularly historical records), or information to fill in gaps or correct errors, via the email address above. Thank you.

This is a list of codes associated with British railway overhead electrification installations. This photograph by Andy Williams shows a prefix code "in action" at Bescot. The "08" shows that the mast is in the 8th mile from the datum, and the "44" that the mast is the 44th within that mile. Some routes, such as the East Coast Main Line, use metric measurements, but the mast numbering principle is the same. For the meaning of other electrification-related signs, this "Railway Signs" page should answer all your questions. One sign not included and commonly seen attached to masts is yellow with black letters "D E P" arranged vertically. This defines a designated earthing point.

In general, schemes up to around 1972 are measured in miles and those after in km (metric measures came in for the northern electrification of the WCML). The WCML (prefix G) switches from miles to km at Weaver Junction so there is a big gap in the numbers there. Also note that the datum points for the masts are not necessarily the same as for milepost milages. For example, on the Manchester Airport line (prefix MIA) the mileage number starts from Heald Green North Junction, but the milepost count runs from Manchester Airport station.

In many cases, the letters refer to the ends of the line of route, the first letter often referring to the datum. Thus DW would be "Dudley to Winchnor", though there are two separate sections electrified. Other letters refer to older conventions of giving each route a letter, and branches off that route a second (and in some cases, third) letter.

Stephen Murray has kindly produced this sketch showing the codes used and codes allocated but not used. Use your browser's "back" button to return to this page. I am aware that this may not display correctly in Safari: if this is the case then a PDF is available.

Code	Area	Unit	Datum
A	Fenchurch Street-Shoeburyness	miles	Fenchurch Street
A	Shoeburyness Depot	miles	Fenchurch Street
A	Guide Bridge Station Junction-Crowthorne Junction (former DC system, now closed)	miles
AB	Gas Factory Junction-Bow Junction (Later code, possibly never used. See also F)
AC	(Former) Cornbrook Junction-Trafford Park (may refer to Allerton Junction to Cornbrook Junction, though not all of this is electrified)	miles
ACF	Trafford Park Freightliner Yard	Allocated, not used?
ACX	Trafford Park Yards	miles	Trafford Park West Junction
AE	Ashburys Yard (former DC system, now closed)	miles
AG	Allerton East Junction-Garston Junction and Garston sidings	miles	Euston
AH	Allerton Junction-Hunts Cross West Junction	miles	Liverpool
AI	Denton Junction-Ashton Moss Junction (former DC system, now closed)	miles
AL	Aston-Lichfield City	km	Aston Junction
AN	Ashton Moss Yard (former DC system, now closed)	miles
AR	Ashburys Top End Yard (former DC system, now closed)	miles
AT	Tilbury loop	miles	Fenchurch Street
AW	Ardwick Yard (former DC system, now closed)	miles
AX	Allerton Depot	miles	Liverpool
AX	Aston Goods (now de-wired)	miles
AY	Apperley Junction-Ilkley	km	St Pancras via Cudworth
B	Glasgow High Street-Helensburgh Central via Singer	miles	Glasgow High Street
B	Liverpool Street-Norwich (measured in miles to Colchester, km thence to Norwich. B prefix not present Bethnal Green (mast 01 01)-Shenfield (some sources state Chelmsford Arbour Lane Overbridge))	miles/km	Liverpool Street
B	Colchester Depot	miles	Liverpool Street
B	Ashburys East Junction-Romiley (start of line) (possibly from Belle Vue. Former DC system, now dewired)	miles	Ashburys East Junction?
BA	Aldersbrook Sidings (Ilford)	Numbered from BA01 from junction with up avoiding line, unrelated to distance
BAT	Battersea Wharf (now de-wired)	miles
BB	Birmingham New Street-Bushbury Junction (via Wolverhampton)	miles	Birmingham New Street
BB	Witham-Braintree	km	Liverpool Street
BB	Dalreoch-Balloch Pier	miles	Dalreoch Junction
BBX	Wolverhampton Freightliner Terminal	miles
BC	Colchester-Clacton	miles	Colchester Junction
BC	Bletchley-Cambridge (electrified at Bletchley only, including depot)	miles	Bletchley East Junction
BCY	Chelmsford Royal Mail Terminal	See BD
BD	Felixstowe Beach Junction-Felixstowe Docks	Allocated, not used
BD	Chelmsford Royal Mail Terminal (One source states that the remains of the link to this terminal uses B, and the terminal itself (now dewired) had BCY. Further observation required)	miles
BE	Manningtree North Junction-Manningtree East Junction	km	Manningtree East Junction
BF	East Suffolk Junction-Felixstowe	Allocated, not used
BF	Asfordby Test Centre Depot ("Building F", named after UK Coal building converted to test centre)	km	Asfordby North Junction
BF	King Edward Bridge South Junction-King Edward Bridge East Junction	Numbered from BF01 at King Edward Bridge South Junction, unrelated to distance
BH	Hyndland Depot branch (now closed)	miles	Partickhill Junction Presumed
BH	Manningtree South Junction-Harwich	km	Manningtree South Junction
BHX	Harwich Parkeston Yard	km	Parkeston West Goods Junction
BJ	Barnsley Junction Sidings (former DC system, now closed)	miles
BL	Lea Junction-High Meads Junction	km	Lea Junction
BM	Stratford Central Junction-Carpenters Road North Junction	km	Stratford Central Junction defined as 3km
BM	Westerton-Milngavie	miles	Westerton Junction
BP	Bescot-Pleck Junction	miles
BR	Sheffield Victoria Electric Lay By Sidings (former DC system, now closed)	miles
BS	Birmingham Curzon Street-Stafford (via Aston/Bescot)	miles	Curzon St
BS	Singer Works branch (now closed)	miles	Singer Works Junction Presumed
BS	Sudbury branch	Allocated, not used
BT	Channelsea North Junction-Temple Mills East Junction	km	Channelsea North Junction
BU	Romford-Upminster	km	Liverpool St via Romford
BW	Hyndland West Curve	miles	Hyndland North Junction
BXD	Bescot Down Side Sidings	miles	Curzon St
BXU	Bescot Up Side Sidings	miles	Curzon St
BY	Norwich Thorpe Junction-Great Yarmouth (only wired for about 1km beside Crown Point Depot)	km	Norwich Thorpe Junction
BY	Hyndland East Junction-Dalmuir via Yoker	miles	Hyndland East Junction
BYX	Norwich Crown Point Depot	km	Swing Bridge Junction?
C	Lancaster Castle branch (1950s scheme; now closed)	Numbering unrelated to distance
C	Bethnal Green-King's Lynn	miles	Liverpool Street
C	Cambridge Depots	miles	Liverpool Street
C	March-Peterborough (only Peterborough end electrified)	km	Peterborough station Presumed
C	Cambridge-Lincoln-"North"	Allocated, not used
C	Gorton-Hyde Road Junction Curve (former DC system, now closed)	miles
CA	Stansted South Junction-Stansted Airport	km	Stansted South Junction
CB	Primrose Hill-Broad St (part now de-wired and removed, part now has prefix V, one CB mast remains at Camden Road)	miles	Broad St
CC	Bury St Junction-Cheshunt	miles	Liverpool Street
CE	Hackney Downs North Junction-Enfield Town	miles	Liverpool Street
CF	Stansted North Junction-Stansted East Junction	km
CH	Clapton Junction-Chingford	miles	Liverpool Street
CI	Camden Road East Junction-Freight Terminal Junction (line rebuilt, now has prefix YN)	miles?
CI	Fairfield-Reddish (former DC system, now closed)	miles
CL	Willesden Empty Carriage Lines	miles	Euston
CL	Gresty Lane Junction-Salop Goods Junction	miles	Euston
CLX	Crewe Works wheel lathe line	miles	Euston
CM	Cheadle Hulme-Macclesfield	miles	Cheadle Hulme Junction
CN	Carlisle-Newcastle (only Carlisle end electrified)	km
CN	Coventry-Nuneaton (ends electrified, centre not electrified. Recent extension of wires at Nuneaton uses km posts, remainder uses miles)	miles/km	Coventry North Junction
CR	Hertford East branch	miles	Liverpool Street
CR	Reddish Depot (former DC system, now closed)	miles
CS	Crewe-Shrewsbury (only electrified Crewe-Gresty Lane)	miles	Crewe South Junction
CU	Upperby Carriage Depot	km	Euston
CVL	Hardendale Quarry connection	km	Euston
CVQ	Hardendale Quarry line (now de-wired)	km	Junction with CVL
CW	Chester-Warrington (only electrified Acton Grange Junction-Arpley Marshalling Yard)	km	Manchester Ship Canal Viaduct
CWX	Arpley Marshalling Yard	km	Arpley Grid Iron Junction
CX	Crewe Electric Depot	miles	Euston
CX	Crewe South Yard	miles	Euston
CX	Nene Carriage Sidings (Peterborough)	km	Peterborough station
D	Cogload Junction-Rotherham via Bristol, Birmingham, Derby and Chesterfield (only electrified Kings Norton-Barnt Green)	km	Redditch
DA	Barnt Green-Redditch	km	Redditch
DB	Birmingham New Street-Kings Norton	km	Redditch
DC	Bescot Curve Junction-Bescot Junction
DE	Stourbridge Junction North-Galton Junction	Allocated, not used
DE	Dunstall Park Junction-Bushbury Junction (only electrified at Dunstall Park Junction end. Source also suggests prefix DB. Code not seen on site. See also OB)	miles
DF	Derby-Trent	Allocated, not used
DG	Dinting-Glossop	miles	Dinting West Junction
DL	Darnall Depot (former DC system, now closed)	miles
DP	Landor Street Junction-Proof House Junction (short section at Proof House end wired? Not seen on site)
DS	Ditton Sidings? (Seen on disused up side masts)	miles	Euston?
DV	Daventry International Rail Freight Terminal (DIRFT)	km?
DW	Dudley-Wichnor (Pleck Junction-Walsall and Lichfield City-Lichfield Trent Valley electrified)		Dudley
DY	Dewsnap Sidings (former DC system, now closed)	miles
E	Kings Cross-Aberdeen (electrified to Haymarket East Junction only)	km	Kings Cross
E	Welwyn Garden City Depot	km	Kings Cross
E	[present at St Botolphs in 1980s]	km	Colchester Junction?
EB	Doncaster-Leeds-Neville Hill Depot	km	Doncaster Marshgate Junction
EB	East Gate Junction-Colchester Town	miles	Colchester Junction
EBL	Hemsworth Loops	km	Doncaster Marshgate Junction
EBN	Leeds Neville Hill Depot	km	Neville Hill West Junction
EBX	Wakefield Cartic Sidings	km	Doncaster Marshgate Junction
EC	Hitchin-Shepreth Branch Junction	km	Kings Cross
EC	Euston Empty Carriage Lines	miles	Euston
ECX	Craigentinny Depot	km	East end of depot
ED	Euston Down Side Carriage Sheds	miles	Euston
EG	Garston Speke Yard (possibly should be SG)
EG	Edge Hill Upper Reception Sidings
EH	Hertford Loop	km	Kings Cross
EH	East Ham Depot (believed some masts only, most use A)	km
EM	Finsbury Park-Moorgate (only wired to Drayton Park (down line)/Highbury & Islington (up line). Up line wiring supports between Drayton Park and Highbury not numbered)	km	Moorgate
EN	Norton Bridge-Stone	miles	Stone
ET	Doncaster-Hull (only short length at Doncaster end wired)	km	Marshgate Junction
EU	Euston Up Side Carriage Sheds	miles	Junction with main lines
EW	Portobello Junction-Monktonhall Junction via Newcraighall	km	Monktonhall Junction
EWA	Low Fell Junction-Norwood Junction	km	Low Fell Junction
EX	Kings Cross Freight Terminal (dewired 19 August 2001)	km	Kings Cross
EX	Hornsey Carriage Sidings and Bounds Green Depot	km	Kings Cross
EX	Ferme Park Down Sidings	km	Kings Cross
EX	Peterborough Eastfield Sidings	km	Kings Cross
EXB	York Works	km
EXD	Doncaster Yard	km
EXD	Doncaster Loversall Junction-Decoy North Junction	km
EXE	Edinburgh Yard (Millerhill Depot)	km
EXG	York avoiding line	km	Holgate Junction
EXH	York Yard head shunt	km	Holgate Junction
EXK	Northallerton Up Sidings	km	Junction with main line
EXR	Tyne Yard	km	Park Lane Junction
EXT	Newcastle King Edward Bridge North Junction to Newcastle East Junction (High Level Bridge)	km	King Edward Bridge South Junction
EXU	Newcastle King Edward Bridge North Junction-King Edward Bridge East Junction	km
EXV	Heaton Depot (south)	km	South Junction?
EXW	Heaton Depot (north)	km	Heaton South Junction
EXX	Heaton Depot service road 4	km	South Junction?
EXY	York Yard	km
EY	Bounds Green Repair Shed	km	Kings Cross
EYX	Alnmouth Up Side Sidings	Believed allocated, not used
EZ	Drem-North Berwick	km	Drem Junction
F	Glasgow High Street-Drumgelloch	miles	Glasgow High Street
F	St Pancras-Clay Cross (electrified to Bedford only)	km	St Pancras
F	Denbigh Hall South Junction-Bletchley flyover	miles	Bletchley Flyover Junction
F	Gas Factory Junction-Bow Junction (Original code. See also AB)	miles	Fenchurch Street
FA	Cricklewood-Acton Lane	Allocated, not used
FB	Forest Gate-Barking (first few masts from Forest Gate Junction numbered sequentially, unrelated to distance, remainder and T&H flyover numbered conventially)	miles	Forest Gate Junction
FB	Glasgow High Street-Bridgeton Central (now closed)	miles	High Street Junction Presumed
FCX	See FXC
FD	Luton-Dunstable (link to main line missing from list)	Allocated, not used
FG	Bedford-Bletchley (reported as small length at Bletchley wired, but no evidence on site)	Allocated, not used?
FH	Leeds Station-Holbeck (code changed to LE)
FL	Farington Junction-Lostock Hall Junction	km	Farington Junction
FM	Kentish Town-Moorgate	km	Moorgate
FP	Hornsey EMU Depot	Numbered FP01 to FP124 from south end of site, unrelated to distance
FS	Bellgrove-Springburn	miles	Bellgrove Junction
FS	Shenfield flyunder (not seen on site; see also L)	miles	Liverpool Street
FW	Holbeck East Junction-Wortley West Junction	Allocated, not used
FXB	Bedford Cauldwell Road Depot	km	Bedford South Junction
FXC	Cricklewood Depot (also erroneously reported as FCX)	km	St Pancras
FXS	Bedford Depot stabling sidings [near station]	km	North end of yard
FXW	Bedford Depot carriage washer lines (Note that the washing machine itself beside the main line carries F masts)	km	North end of yard
FY	Finnieston West Junction-Finnieston (Exhibition Centre) Station (Up Argyll Line) (most masts do not carry numbers)	km	Stobcross Tunnel
G	Glasgow Central-Eglinton Street Junction	miles	Glasgow Central
G	Euston-Eglinton Street Junction (including Crewe carriage shed/Brook sidings) (measured in miles to Weaver Junction, then in km northwards)	miles/km	Euston
G	Glossop-Hadfield (former DC system, now DG?)	miles	Glossop?
GA	Watford Junction-St Albans Abbey	km	Watford Junction
GA	Milnwood Junction-Mossend East Junction	km	Mossend East Junction
GB	Rugby-Birmingham New Street	miles	Euston
GB	Springs Branch-Bamfurlong flyunder	km	Euston?
GB	Mossend South Junction-Mossend West Junction	km	Mossend South Junction
GB	Carnforth-Barrow (only electrified at Carnforth end)	km	Euston
GC	Crewe-Chester (section to Steelworks Junction wired)	miles	Euston
GC	Cathcart Circle	miles	Eglinton Street Junction (anticlockwise)
GCW	Crewe Works	miles	Junction with Chester line at works entrance
GD	Motherwell-Garnqueen North Junction including Mossend Yard (electrified to Gartsherrie South Junction only)	km	Motherwell Lesmahagow Junction
GDM	Motherwell Depot	km	South end of depot
GE	Glossop-Hadfield (former DC system, now HJ)	miles
GE	Winwick Junction-Earlestown	km	Winwick Junction
GE	Carstairs East Junction-Edinburgh Haymarket East Junction	km	Carstairs East Junction
GEN	Carstairs Station Junction-Carstairs East Junction	km	Carstairs Station Junction
GES	Carstairs East Junction-Carstairs South Junction	km	Carstairs South Junction
GF	Gushetfaulds Junction-Gushetfaulds Freight Liner Terminal (now de-wired)	km?	South end of depot?
GH	Hamilton Loop	km	Motherwell Lesmahagow Junction
GHL	Larkhall Branch	km	Haughhead Junction
GJ	Cathcart West Junction-Neilston	miles	Cathcart West Junction
GK	Cathcart North Junction-Newton West Junction	miles	Cathcart North Junction
GL	Cathcart East Junction-Cathcart West Junction	miles	Cathcart East Junction
GL	Garston Yard (Speke Junction area) (now carries prefix LX)	miles
GL	Weaver Junction-Liverpool Lime St (first approx 2 miles (GL175/xx and GL176/xx) over flyover as far as M56 bridge, see also L)	miles	Euston
GM	Crewe-Manchester Oxford Road (first few masts to about 159 mile post, see also M)	miles	Euston
GM	Uddingston Junction-Law Junction via Holytown	km	Law Junction
GN	Mossend North Junction-Mossend East Junction (Fullwood Junction)	km	Mossend East Junction
GP	Shieldmuir Junction-Wishaw Central Junction	km	Wishaw Central Junction
GPD	Polmadie Depot Downside sidings	km	South end of depot
GPU	Polmadie Depot Upside Sidings	Allocated, not used (sidings use G)
GRM	Shieldmuir Royal Mail Terminal loop	km	South end of loop
GS	Lanark branch	km	Lanark Junction
GT	Holytown Junction-Midcalder Junction	Allocated, not used
GT	Gasworks Tunnel	Numbered from GT01 at south end of tunnel, unrelated to distance
GW	Shields Junction-Larkfield Junction	miles	Larkfield Junction
GW	Glossop West Curve (former DC system, now DG)	miles	Dinting?
GX	Bletchley Up Yard carriage sidings	miles	Euston
GX	Crewe Down Independent lines	miles	Euston
GX	Nuneaton Down Sidings	miles	Euston
H	Marylebone lines	Allocated, not used
H	Didcot East Junction-Bordesley Junction via Oxford	Allocated, not used
HB	Perry Barr North Junction-Perry Barr West Junction	miles	Perry Barr North Junction
HC	Macclesfield Hibel Road-Colwich	miles	Macclesfield Hibel Road
HD	Smethwick West-Bordesley South Junction via Moor Street	Allocated, not used
HF	Halton Junction-Frodsham Junction (electrified at Halton Junction end only)	miles	Halton Junction
HH	Hartford LNW Junction-CLC Junction (electrified at Hartford LNW Junction end only)	miles	Hartford LNW Junction
HJ	East side of Dinting triangle	miles
HK	Coventry-Leamington Spa via Kenilworth	Allocated, not used
HL	Hythe Junction-Colchester Town	miles	Starts at 1 mile at Colne Junction
HO	Spur through Hyde North (former DC system, now closed)	miles
HP	St Andrews Junction-Proof House Junction (short spur at the Proof House end? Not seen on site)
IL	Ilford carriage sheds	Numbered IL01 to IL66A from west end of site, unrelated to distance
J	Paddington-Swansea (electrified to Heathrow Airport Junction only)	km	Paddington
JH	Heathrow Airport Junction-Heathrow Terminal 4	km	Paddington
JJ	Heathrow Terminals 1, 2, 3-Heathrow Terminal 5	km	Paddington
K	Reading-Penzance (via Berks and Hants Line)	Allocated, not used
KC	Coventry-Leamington Spa (electrified at Coventry end only)	miles	Leamington Spa
KC	Kidsgrove-Crewe	miles	Kidsgrove Junction
KC	Crewe North Staffordshire curve (closed 1 October 1984)	miles	Euston
KYD	Kingmoor Down Yard	km	Euston
KYU	Kingmoor Up Yard	km	Euston
L	Glasgow Bridge Street Junction-Gourock	miles	Glasgow Bridge Street Junction
L	Glasgow Smithy Lye sidings (dewired 2007)	miles	Glasgow Bridge Street Junction
L	Letchworth sidings	km	Kings Cross
L	Weaver Junction-Liverpool Lime St (see also GL)	miles	Euston
L	Shenfield flyunder (LNER code still used; see also FS)	miles	Liverpool Street
L	Colchester flyunder (LNER code still used)	miles	Liverpool Street
LA	Paisley-Ayr	km	Ayr side of Paisley Gilmour Street station
LA	Leeds West Junction-Engine Shed Junction	km	Leeds North Junction
LAX	Ayr (Townhead) Sidings	km	Junction with main line
LB	Largs branch	km	Kilwinning Junction
LC	Shields Junction-Corkerhill Depot	miles	Shields Junction
LCX	Corkerhill Depot sidings	miles
LD	Byrehill Junction-Dubbs Junction	km	Dubbs Junction
LE	Leeds Whitehall Junction-Engine Shed Junction (code was FH)	km	Whitehall SW Junction
LG	Willesden Low Level Goods Line	miles	Euston
LH	Liverpool Edge Hill-Hull via Manchester Victoria and Leeds (only Leeds Whitehall Junction-Copley Hill West Junction wired)	km	Liverpool Edge Hill
LL	Crewe Low Level lines	miles	Euston
LL	Salop Goods Loop Junction-Gresty Lane Junction	miles	Euston
LM	Liverpool-Manchester (electrified Edge Hill-Olive Mount Junction (miles), and Earlestown-Newton le Willows Junction (km))	miles/km	Liverpool Lime St
LM	Hunts Cross-Hunts Cross West Junction, plus short stretch towards Garston	miles	Liverpool
LN	Ardrossan Harbour branch	km	Holme Junction
LO	Godley Junction-Apethorne Junction (former DC system, now closed)	miles
LS	Leeds-Skipton	km	St Pancras via Cudworth
LS	Glasgow Shields Depot		East end of site
LW	Wemyss Bay branch	miles	Wemyss Bay Junction
LW	Huyton-Wigan (Springs Branch Junction)	Allocated, not used
LX	Halewood Ford Plant	miles	Euston
LX	Runcorn-Folly Lane branch (now de-wired)	miles	Runcorn
LX	Used in the Edge Hill area	miles	Euston
LY	Micklefield Junction-Church Fenton North Junction	Allocated, not used
M	Lancaster Green Ayre-Morecambe (1950s scheme; now closed. Experimental masts carried X)	Numbering unrelated to distance, believed to run M1 to M178 from Green Ayre
M	Crewe-(almost) Deansgate (see also GM)	miles	Euston
M	Stub of Heaton Norris-Guide Bridge branch (Masts are all M183 71, with suffix A to P)	miles	Euston
M	Mottram Yard (former DC system, now closed)	miles
MA	Manchester Oxford Road-Altrincham (reused for Manchester Metrolink, still used Deansgate-Cornbrook Junction)	miles	Euston (main line)/ Manchester Oxford Road (Altrincham branch)?
MAS	Manchester Airport south curve	km	Heald Green South Junction
MB	Manchester-Bury (does not apply to Manchester Metrolink)	Allocated, not used
MH	Ardwick-Hadfield (see also OB)	miles	Ardwick Junction
MIA	Heald Green North Junction-Manchester International Airport	km	Heald Green North Junction
ML	Euxton Junction-Manchester Deal Street Junction via Bolton	Allocated, not used
MO	Mottram Yard (former DC system, now closed)	miles
MR	Mottram Yard (former DC system, now closed)	miles
MS	Mottram Sorting Sidings (former DC system, now closed)	miles
MT	Muirhouse Central Junction-Terminus Junction	km	Muirhouse Central Junction
MWL	Longsight wheel lathe road and Eurostar shed	miles	Euston
MX	Manchester Longsight Depot carriage sheds	miles	Euston
MXH	Manchester Longsight Depot outer roads ("old coal yard")	miles	Euston
N	Water Orton East Junction-Norwich via Leicester, Ely and Peterborough (electrified for small section through Nuneaton only)	km	Water Orton East Junction
NA	Nuneaton-Whitacre Junction (electrified for small section of Nuneaton Abbey curve only)	miles	Whitacre Junction
NPD	North Pole Depot Departure Road	km	Junction with NPW (just east of West London Line bridge)
NPE	North Pole Depot East Side	km	Junction with NPW (just east of West London Line bridge)
NPM	North Pole Depot Maintenance Shed	km
NPW	North Pole Depot West Side	km	West end of yard
NPX	North Pole Depot East Sidings/Wheel Drop	km
NW	Nuneaton-Wigston Junction (electrified at Nuneaton end only. Now dewired.)	miles	Nuneaton South Junction
NX	Northampton Down Side Sidings (rebuilt as maintenance depot, retains prefix)	miles	Euston
NX	Northampton Siemens Traincare Depot	miles	Euston
OB	Ardwick-Hadfield (a few masts under the M60: numbered "OB 18B <individual number>". See also MH)	n/a	n/a
OB	Dunstall Park Junction-Bushbury Junction (electrified at Dunstall Park Junction end only)	miles
P	London Marylebone-Birmingham Snow Hill	Allocated, not used
PA	Neasden Midland-Neasden Junction	Allocated, not used
PB	Preston-Blackpool (electrified at Preston end only)	km	Preston Fylde Junction
PD	Pleck Junction-Darlaston Junction	miles	Darlaston Junction
PG	Newton-le-Willows (Parkside)-Golbourne Junction	km	Newton-le-Willows Junction
PH	Soho South Junction-Perry Barr South Junction	miles	Perry Barr South Junction
PH	Pelaw-Sunderland	km	Pelaw
PHS	Sunderland-South Hylton (also appears to have numbers of the form "O/BR014")	km	Pelaw
PHX	Sunderland station (also appears to have numbers of the form "O/BR255")	km	Pelaw
PT	Wolverhampton-Portobello Junction	miles	Portobello Junction
RF	Finnieston East Junction-Rutherglen	km	Rutherglen Central Junction
RG	Ryecroft Junction-Rugeley (electrified at Rugeley end only)	miles	Ryecroft Junction
RM	Warrington Dallam Royal Mail Terminal (note that the measuring unit is not the same as the adjacent main line)	miles	Euston
RR	Roade-Rugby via Northampton	miles	Euston
RT	Tilbury East Junction-Tilbury South Junction	miles	Tilbury East Junction
RW	Rutherglen West Curve	km	Rutherglen West Junction
RX	Rugby Peterborough Branch siding	miles	Euston
S	Shenfield-Southend (LNER code still used)	miles	Liverpool Street
S	Southend Victoria Depot	miles	Liverpool Street
SA	Stechford-Aston	miles	Stechford
SA	Willesden Sudbury Arrival Sidings	miles	Euston
SB	Stockport-Buxton (electrified to Hazel Grove only)	miles	Edgeley Junction
SB	Shipley-Bradford Forster Square	km	St Pancras via Cudworth
SC	Stratford Central Junction-Copper Mill Junction	km	Stratford Central Junction
SC	Skellow Junction-Carcroft Junction	Allocated, not used
SC	Slateford Junction-Craiglockhart Junction	Allocated, not used
SC	Unknown route near Crewe	miles	Euston
SCX	Temple Mills Yard (now dewired)	km	Stratford Central Junction
SCX	Stratford Orient Way Sidings	km	Junction with main line
SCZ	Temple Mills Yard (now dewired)	km	Junction between East Yard and West Yard?
SE	Shipley-Guisley	km	Esholt Junction
SG	Speke Junction-Garston Dock	miles	Euston
SG	Stonebridge Park Sidings	miles	Euston
SN	Sandbach-Northwich (electrified at Sandbach end only)	miles	Sandbach
SO	Wilmslow-Slade Lane Junction (Styal Loop)	miles	Wilmslow
SO	Guide Bridge West Junction-Dukinfield (former DC system, now closed)	miles
SS	Wickford-Southminster	km	Liverpool Street
SS	Soho North Junction-Soho East Junction	miles	Soho East Junction
ST	Seven Sisters Junction-South Tottenham West Junction (two sequential masts near Seven Sisters Junction are numbered ST 0 11 and ST 1 12)	miles	South Tottenham West Junction
SW	Stafford-Wellington (electrified at Stafford end only; remainder of line lifted)	miles	Uttoxeter Line Junction
SW	Shipley West Curve	km	Shipley South Junction
SW	Crewe Works (one line, two masts only)		Traverser
SX	Stafford Salop Sidings	miles	Euston
SX	Unknown route near Crewe	miles	Euston
T	Torresholme triangle southbound curves (Lancaster) (1950s scheme; now closed. Probably includes route south to Heysham)	Numbering unrelated to distance
T	Tinsley Yard (former DC system, now closed)	miles
T	Tunnels on Woodhead route (former DC system, now closed)	miles
TB	Tottenham and Hampstead Line (only wired at Woodgrange Park Junction end of line)	miles	St Pancras via Upper Holloway
TC	Tottenham South Junction-South Tottenham West Junction	miles	Tottenham South Junction
TD	Temple Mills Eurostar Depot connecting line	km	Stratford International station
TF	Tilbury Freightliner yard	Numbered from TF01 from Grays East Junction, unrelated to distance
TG	Carlisle Through Goods Line (now electrified Upperby Bridge Junction-Upperby Junction; formerly electrified to Caldew Junction)	km	Upperby Bridge Junction
TH	Thornton Field sidings (dewired June 2008)	Numbered from TH01A from Thornton Field Junction, unrelated to distance
TM	Temple Mills Eurostar Depot	km	Stratford International station
TMD	Stratford Traction Maintenance Depot (now closed)
TR	Tilbury Riverside Triangle (West Side) (now dewired)	miles	Fenchurch St via Dagenham Dock
TS	Romford OLE Depot ("Training Span")	km	West end of yard
TS	Rugby On Track Machine Depot ("Training Span")	km?	Junction with former Peterborough branch
TS	Willesden Princess Royal Distribution Centre ("Terminal Shed")	miles?
TT	Alstom Midlands Test Centre ("Test Track")	km	Asfordby tunnel north portal
TW	Thorpe le Soken-Walton on Naze	miles	Colchester Junction
UG	Upminster-Grays	miles	Upminster Junction
UL	High Level Goods Line	miles	Euston
V	Carpenters Road South Junction-Camden Junction	km	Camden Junction (on West Coast Main Line)
VC	Reading Lane Junction-Navarino Road Junction	km	Navarino Road Junction
VE	Finsbury Park-Canonbury	Numbered from VE01 from Canonbury West Junction, unrelated to distance
VS	Carpenters Road North Junction-Stratford (New route parallel to Channelsea curve)	km	Carpenters Road North Junction
VW	Channelsea-North Woolwich	Allocated, not used
W	Wath branch (former DC system, now closed)	miles	Barnsley Junction
WA	Edge Hill Wapping Branch	miles	Euston?
WB	West London Junction (Willesden)-North Pole (now WE)	miles	West London Junction
WB	Willesden Brent Sidings (now de-wired)	miles
WBX	Brent Sidings, Princess Royal Distribution Centre	miles	Euston
WC	Willesden Carriage Sidings/Wembley Traincare Depot	miles	Euston
WD	Willesden Traction Maintenance Depot	miles	Euston
WE	West London Junction (Willesden)-Kensington Olympia (formerly WB. Electrified to 4m 73ch only)	km	West London Junction
WE	Wath Exchange Sidings (former DC system, now closed)	miles
WF	Willesden Freightliner Terminal	miles	South end of site
WG	Camden Road Junction-(a little south of) Acton Central	km	Camden Road Junction
WH	Kensal Green Junction-Willesden Low Level Station (electrified at Kensal Green Junction end only)	km	Kensal Green Junction
WJ	Kensal Green Junction-Willesden Junction (City Goods Line)	km	Kensal Green Junction
WK	Willesden High Level Junction-Mitre Bridge Junction	km	Willesden High Level Junction
WL	Earlestown South Junction-West Junction	Allocated, not used
WL	Acton Wells Junction-West London Junction	Allocated, not used
WM	Acton Wells-Willesden Freight Terminal Junction (small portion electrified at Acton Wells end)	km	Acton Wells Junction
WN	Acton Wells-Acton East Junction	Allocated, not used
WN	Niddrie North Junction-Niddrie West Junction	Allocated, not used
WP	Water Orton Junction-Park Lane Junction	Allocated, not used
WS	Niddrie South Junction-Niddrie West Junction	Allocated, not used
WS	Wolverhampton North Junction-Oxley Carriage Sidings	miles?	Wolverhampton North Junction
WS	Whifflet South Junction-Sunnyside Junction	km	Whifflet South Junction
WS	Watford-St Albans (Watford sidings only now with this prefix; remainder now GA)	miles	Watford
WSL	Oxley Carriage Sidings (down loop?)	km	South end of site
WSX	Oxley Carriage Sidings	km	South end of site
WTX	Willesden Wembley Train Operations Centre	miles	End of yard
WW	Wavertree Junction-Wapping Branch (now closed)	miles	Wavertree Junction
WW	Wath West Departure Sidings (former DC system, now closed)	miles
WX	Wavertree Yard	miles	Euston
X	Grantham down side sidings	km	Grantham South Junction
X	Ovangle Bridge-Carlisle Bridge (Lancaster area) (1950s scheme experimental masts, others were M; now closed)	Numbering unrelated to distance
X	Cowlairs West Junction-Dundee Central Junction	Allocated, not used
XC	Carmuirs East Junction-Larbert Junction	Allocated, not used
XEB	Wakefield Wrenthorpe Sidings	km	Doncaster Marshgate Junction
XG	Gartcosh Junction-Gartsherrie South Junction	Allocated, not used
XP	Polmont Junction-Carmuirs West Junction	Allocated, not used
XQ	Greenhill Lower Junction-Greenhill Upper Junction	Allocated, not used
Y	St Pancras-Channel Tunnel boundary	km	St Pancras
Y	Channel Tunnel boundary-Dollands Moor-Saltwood Tunnel (code changed to YS)	km	St Pancras?
YA	Ashford station loop of Channel Tunnel Rail Link	km	Ashford West Junction
YAX	Dollands Moor Yard	km	St Pancras?
YC	Silo Curve (Link from St Pancras to North London Line)	km	St Pancras
YD	Yoker Depot	miles	East end of depot
YD	Freight line from CTRL to Dollands Moor yard	km	Dollands Moor West Junction
YF	Singlewell Junction-end of OLE near Fawkham Junction	km	Datum defined as 200km
YK	Ebbsfleet-Springhead Junction	km	Ebbsfleet
YKX	Ebbsfleet turnback sidings	km	Ebbsfleet
YN	North London ("Kings Cross") Incline	km	Camden Road Central Junction
YR	Ripple Lane chord	km	St Pancras
YRX	Ripple Lane exchange sidings	km	Renwick Road Junction
YS	Channel Tunnel boundary-Dollands Moor-Saltwood Tunnel (code was Y)	km	St Pancras?
YW	Camden Road Central Junction to Channel Tunnel Rail Link connection	km	Camden Road Central Junction
	former Woodhead route (Route never had a prefix code, though masts were still numbered according to distance. Former DC system, now closed)	miles	Manchester

Note regarding "G" codes near Glasgow: masts are numbered from G/0/1 upwards across the Clyde covering all lines to Bridge Street Junction, and then continue to Eglinton Street Junction. Here they meet "G" series masts counting from Euston.

Codes not certain (confirmation would be welcome)

Code	Area	Unit	Datum
	None at present

Suspicious data

This data comes from an unverified source, and should be treated with caution. If you know of the veracity of these codes, please contact me.

Code	Area	Unit
H	Paddington-High Wycombe (code allocated to Marylebone lines, see above)	Allocated, not used
LG	Bridge Street Junction-Gourock (thought to have ben allocated, but duplicated in L above)
SAO	Wolverhampton-Stetchley (cannot locate Stetchley: probably Stetchford)
TH	Woodgrange Park Junction-start of line-Gospel Oak (reported, but duplicated in TB above)
WB	Gospel Oak-Woodgrange Park (reported allocated, probably not used: small section of line at Gospel Oak wired using WG masts)
WM	Wanton Watts Junction-Millerhill (possibly allocated, but duplicated in EW above)

An odd one to complete the record

Code	Area	Unit	Datum
XX	Ripple Lane area (reported, but taken to mean "fill in details later" and published in official documentation in error)

Codes not known (Please contact me if you can supply missing data)

Carstairs sidings (masts are unlabelled: allocated G or GEN?)
Kingmoor sidings and depot
Letchworth Depot (masts appear unlabelled)
Bounds Green Depot (lines to former Palace Gates station)
Shildon-Newport and associated yards
LBSC/Southern Railway overhead system
    (London Bridge - Victoria via Denmark Hill opened 1909)
    (Battersea Park - Crystal Palace via Streatham Hill opened 1911)
    (Peckham Rye - Streatham Hill opened 1911)
    (Peckham Rye - Crystal Palace via Tulse Hill opened 1911)
    (Balham - Coulsdon North opened 1925)
    (Balham - Sutton opened 1925)
Southern region overhead electrified yards
Bury-Holcombe Brook (used 1912-c1950)
Lancaster-Morecambe and branches (used from 1908)
Ashford Hitachi depot (single overhead track for testing Javelin units)
Magnus Volk's "Daddy Long Legs" railway
Birmingham Curzon Street branch and mail sidings (dewired c1990)
Duddeston carriage sidings/wagon repair shop (now dewired)
Wolverhampton steel terminal (dewired 1980s/1990s)
Nuneaton up sidings (lifted c2003)
Preston North Union yard (part dewired 2000/01?)
Geldard Road Junction to Leeds via Farnley viaduct (closed late 1990s?)

Channel Tunnel

Masts do not have a prefix letter, but are measured from a fixed datum in the same way as the national system.

Croydon Tramlink

Croydon Tramlink mast references can be found on the Croydon Tramlink Unofficial Site.

Tyne & Wear Metro

Tyne & Wear Metro masts (excluding the Network Rail-owned portion, see above) use a different system, whereby the masts act as distance markers from the datum point near South Gosport Junction. Prefixes are based on electrical sections, the "joining" mast carrying three letters. Section codes known at present are:

B (Benton)
B (Byker)
C (Chichester)
G (Gosforth)
H (Hebburn)
M (Manors)
M (Monument)
N (unknown)
O (Old Ford [now Gateshead Stadium])
S (St James)
S (South Shields)
P (Percy Main)
W (Whitley Bay)
X (used in sidings)
Y (unknown)

Known prefixes are:

CS (eastbound), and SC (westbound)
HCS (eastbound), and SCH (westbound)
HC (eastbound), and CH (westbound)
OHC (eastbound), and CHO (westbound)
OH (eastbound), and HO (westbound)
HOX (in Pelaw sidings)
HON (westbound, on tunnel wall at Gateshead Stadium)
MO (southbound), and OM (northbound)
MG (northbound), and GM (southbound)
MGY (eastbound at Gosforth triangle), and GMY (westbound)
GBY (eastbound at Gosforth triangle), and BGY (westbound)
GB (eastbound), and BG (westbound)
GBx (Benton sidings: last character unknown)
GBW (eastbound), and WBG (westbound)
BW (eastbound), and WB (westbound)
BWP (eastbound), and PWB (westbound)
WP (westbound), and PW (eastbound)
WPX (North Shields bay platform)
WPB (westbound), and BPW (eastbound)
PB (westbound), and BP (eastbound)
PBM (westbound), and MBP (eastbound)
BM (westbound), and MB (eastbound)
MBX (believed present in Stoddart Street sidings)
MS (westbound), and SM (eastbound)
E (believed used on Gosforth depot avoiding line)

Other "joining" mast codes can be inferred but were not seen on my recent visit. Codes on the Airport branch are unknown, and the link line between Manors and Jesmond appears not to carry a prefix at all.

Nottingham Express Transit

Nottingham Express Transit mast references can be found on the NET Trams Unofficial Site.

Midland Metro

Masts are prefixed B for the Birmingham-bound track, and W for the Wolverhampton-bound track. It is not known how the depot masts are labelled.

Manchester Metrolink

Code	Area	Unit	Datum
AC	Used near Cornbrook	Masts are given unique numbers unrelated to distance from any datum
BV	Bury-Victoria	km	Bury
CC	City Centre (Piccadilly to G-Mex and beyond (but not displayed Piccadilly Gardens - St Peters Square); Piccadilly to Victoria)	Masts are given unique numbers unrelated to distance from any datum
CG	Cornbrook-GMex	miles	near GMex
ES	Eccles route (see also EU)	km	Manchester Oxford Road?
EU	Eccles route (see also ES)	km	Manchester Oxford Road?
MA	Altrincham route (masts reused from BR)	miles	Manchester Oxford Road

Queen's Road Depot codes are unknown

Sheffield Supertram

Masts are labelled according to the nearest stop.

Code	Area
ARR	Arbourthorne Road
ARS	Arena/Don Valley Stadium
ATT	Attercliffe
BAS	Bamford Street
BDH	Beighton/Drake House Lane
BIL	Birley Lane
BMR	Birley Moor Road
CAR	Carbrook, and Valley Centertainment
CAS	Castle Square
CAT	Cathedral
CIH	City Hall
CIR	Cricket Inn Road
CRP	Crystal Peaks
DOW	Donetsk Way
FIS	Fitzallan Square/Ponds Forge
GLT	Gleadless Townend
GRR	Granville Road/Sheffield District College, and Park Grange Croft
HAC	Hackenthorpe
HAL	Halfway
HEP	Herdings Park
HIL	Hillsborough
HIP	Hillsborough Park
HLR	Herdings/Leighton Road
HOL	Hollinsend
HYP	Hyde Park
INR	Infirmary Road
LEL	Leppings Lane
LPV	Langsett/Primrose View
MAB	Malin Bridge
MID	Middlewood
MEI	Meadowhall Interchange
MOW	Moss Way
MTE	Manor Top/Elm Tree
NCS	Nunnery Square Park & Ride (unsure to what the "C" refers)
NDP	Nunnery Depot
NER	Netherthorpe Road
PAG	Park Grange, and Park Grange Croft
POLE	Single mast in city centre triangle (numbered 0000)
SHA	Shalesmoor
SHS	Sheffield Station/Sheffield Hallam University
SPL	Spring Lane
TIN	Meadowhall South/Tinsley
UOS	University of Sheffield
WAT	Waterthorpe
WED	Westfield
WES	West Street
WHL	White Lane
WOR	Woodburn Road

With thanks to...

David E Belcher for the initial idea and initial data; David Birch for copious quantities of notes and encouragement; Walter Turner for sharing expertise and a West Coast main line technical paper, and verifying so much with site visits; Paul Robertson, Andy Williams, Garry Keenor, Richard Smith, Jeremy Barker, Brian Carter, Paul Steane, Derek Small, Robert Wilkins, Tony Baker, Aron Moran, John Salmon, Phil Lockwood, Enid Vincent, Martyn Brailsford, Dave Stuttard, Dave Coxon, Stephen Murray, Paul Burroughs and Mike Christelow for additional data.

visits to the electrification pages since 5th February 2007
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