London Transport Signal and IMR codes

London Underground Railways Signalling is a subject in its own right, and it can be a fascinating subject to follow up. The underground system is made up of the following LU Signal Box and IMR*s - Interlocking Machine Rooms.

Here are the codes for all London Transport lines at present, plus some past codes - most codes were just single letters originally and later began to be prefixed with another letter (usually the line initial) for more precise recognition - all codes in this list have been verified to be correct.

Bakerloo Line
Queens Park - BB
Paddington - BD
Baker Street - BM
Piccadilly Circus - BP
Lambeth North - BR
Elephant - BS

Victoria Line
Brixton - VE
Victoria - VF
Warren Street - VG
Kings Cross - VH
Highbury - VJ
Finsbury Park - VK
Seven Sisters - VL
Northumberland Park
Depot - VN
Walthamstow Ctrl - VP

Circle Line/Met codes 1904-1950's
A - Praed Street (later Edgware Road)
B - Baker Street
C - King's Cross
D - Farringdon
E - Barbican
F - Moorgate
G - Liverpool Street
H - Aldgate
Circle Line/H&C Codes 1950's-Present
OB - Aldgate/Aldgate East
OD - Liverpool Street
OE - Moorgate
OG - Barbican
OH - Farringdon
OJ - Kings Cross
MB - Baker Street
OP - Edgware Road
OR - Paddington Suburban
OS - Westbourne Park
OU - Ladbroke Grove
OZ - Hammersmith
Metropolitan Main Line (original codes)
B - Baker Street
D - Finchley Road
E - Willesden Green
F - Neasden
G - Wembley Park
H - Harrow South
J - Harrow Main
N - Harrow North
P - Rayners Lane
R - Eastcote
V - Hillingdon
W - Uxbridge
Ruislip cannot be confirmed in this series.
Piccadilly Line - Original Codes (Present Codes)
Codes west of Barons Court are under the District 'W-' series.

A - Hammersmith Pic (WD from 1932)
B - Down Street/Hyde Park Cnr (now PB)
C - Covent Garden
D - Holborn (now PD)
E - York Road
F - Finsbury Park (now VK)
G - Wood Green (now PG)
J - Arnos Grove (now PJ)
K - Oakwood (now PK)
M - Cockfosters (now PM)
Central Line (Pre-resignalling)
West Ruislip CS
Ruislip Gardens CS (subsiduary to West Ruislip)
Northolt - CP
Greenford - CL
Ealing Bdy - WP (was L)
North Acton - CJ
White City - CG (was G)
Shepherd's Bush - CF (was F)
Queensway - CE (was E)
Marble Arch - CD (was D)
Holborn - CC (was C)
Bank - was B
Liverpool St - LB (was A)
Bethnal Green  - LC
Stratford - LD
Leyton - LE
Leytonstone - LF
Snaresbrook - LG
South Woodford - LH
Woodford - LJ
Grange Hill subsiduary box to Hainault LL (unoffically LK)
Hainault LL
Fairlop - LM
Barkingside - LN
Newbury Park - LP
Loughton - LT
Debden - LU
Theydon Bois - LV
Epping - LW
North Weald (until 1976) - LX
Ongar - LX
District/Piccadilly codes west of Earls Court begun with W, those east beginning with E - those principles remain more or less today.

WA - Earls Court West (now EC)
WB - West Ken East/Olympia
WC - West Ken West
WD - Hammersmith
WE - West Brompton
WF - Parsons Green
WG - Putney Bridge
(WH) - Junction with LWSR at ravencscourt Park?
WK - Turnham Green
WL - Acton Town
WM - Ealing Common
(WN - Hanger Lane Jcn (WM from 1925)?)
WP - Ealing Broadway
WQ - South Acton
WR - Northfields
(WS - Boston Manor (until 1932)?)
WT - Hounslow Central
WU - North Ealing (closed)
WV - South Harrow
WW - Hatton Cross (was Sudbury Hill)
WX Hounslow West (until 1975)
WY - Heathrow

EA - Earls Court East (now EC)
EB - High St Ken (now ED)
EC - Earls Court (was Cromwell Rd)
ED - High St Ken (present)
EE - Gloucester Road
EF - South Kensington
EG - St James Park (Closed)
EH - Embankment
EJ - Tower Hill (was mansion House)
EK - Minories Junction (Now OB)
EL - Aldgate East (Now OB)
(EM - St Marys Jc until part of EN?)
EN - Whitechapel
EP - Bow Road (closed)
ER - Surrey Quays
ET - New Cross area

B - Shoreditch/Whitechapel (ELL)
OB - Aldgate East

FB - Bromley
FC - Plaistow
FE - East Ham
FF - Barking
FG - Dagenham East
FJ - Hornchurch
FM - Upminster
Northern Line Original Series
A - Kennington (when all autos prefixed S)
B - Kennington (present)
C - Charing Cross
D - Mornington Crescent (until 1924)
E - Camden Town/Mornington Cres (from 1924)
F - Hampstead
G - Golders Green
J - Euston (+ Kings Cross from 1967)
K - Angel
L - Kings Cross (loop only from 1967)
M - Moorgate
P - London Bridge
U - Stockwell
T - Clapham Common
W - Tooting Bdy
Y - Morden
Z - Morden Depot (not official)

1920's extension codes
AA - Brent Cross
AB - Hendon Central
AC - Colindale
AE - Edgware

1930's extension codes
NC - Drayton Park/Finsbury Park
ND - Moorgate (Northern City)
NH - Park Junction (now Highgate Depot)
NN - Archway
NP - East Finchley
NQ - Finchley Central/Mill Hill
NS - Woodside Park
NT - Totteridge
NU - High Barnet
NV - Mill Hill East (now NQ)
Metropolitan Main Line Present Series
MB - Baker Street
MD - Finchley Road (+W Hampstead until 1985, now JD)
ME - Willesden Green (JE from 1985)
MF - Neasden (now MM)
MG - Wembley Park
MH - Neasden Depot North End (closed)
MK - Stanmore/Canons Park (JL from 1985)
ML - Swiss Cottage
MM - Neasden (present)
MP - Rayners Lane
MR - Eastcote
MU - Ruislip
MV - Hillingdon
MW - Uxbridge

JB - Harrow
JD - Finchley Road/W Hampstead Jubilee (from 1985)
JE - Willesden Green (from 1985)
JF - Northwood (was Neasden)
JG - Wembley Park Jubilee (1985)
JJ - Watford South
JL - Stanmore (from 1985)
JP - Watford/Rickmansworth
JT - Chalfont/Chesham
JW - Amersham
Jubilee Line
Stanmore - JL (MK until 1985)
Canons Park - MK
Wembley - JG (MG until 1985)
Neasden - JF (MF until 1985)
Willesden Green - JE (ME until 1985)
West Hampstead/Finchley Rd - JD (MD until 1985)
Baker Street - BM
Green Park - TF
Charing Cross - TG
Waterloo - TH
London Bridge - TJ
Canada Water - TK
Canary Wharf - TL
North Greenwich - TM
Southwark - TP
Bermondsey - TR
West Ham - TU
Stratford Market Depot - TY
Stratford - TW
 

 

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