Signal box prefix codes

A (hopefully) comprehensive listing

'Boxes beginning M

Last update 27 July 2021

Additional information is always gratefully received, whether entirely new records (particularly historical records) or information to fill in gaps or correct errors, via the contact link under the Miscellaneous entry in the navigation bar above. Thank you.

Please select a starting letter from the links below:

Code Signal Box Note ELR Mileage Opened Closed Control to
MD Macclesfield CMD1 0m 20ch 20 March 1965
Macclesfield Central See Macclesfield Old
MN Macclesfield Old Named Macclesfield Central to 10 March 1961 then Macclesfield Station to 20 March 1965 CMD1 ≈0m 19ch 16 July 1933 19 December 1965 last train; 1 October 1966 official Macclesfield (MD)
Macclesfield Station See Macclesfield Old
MH Machynlleth SBA2 75m 4ch 26 March 1960 19 March 2010 Machynlleth Signalling Control Centre (MH)
AS Aberystwyth control boards. Code used from 23 September 1988
BM Barmouth control boards. Code used from 23 September 1988
DJ Dovey Junction control boards. Code used from 23 September 1988
HL Harlech control boards. Code used from 23 September 1988
MT Machynlleth control boards. Code used from 23 September 1988
NT Newtown control boards. Code used from 23 September 1988
PM Porthmadog control boards. Code used from 23 September 1988
PW Pwllheli control boards. Code used from 23 September 1988
TD Talerdigg control boards. Code used from 23 September 1988
TW Tywyn control boards. Code used from 23 September 1988
WP Welshpool control boards. Code used from 23 September 1988
MH Machynlleth Signalling Control Centre ERTMS block markers. Opposite side of line to 1960 box SBA2 75m 4ch 19 March 2010
CP Signals protecting Coe Pawb flat crossing with Welsh Highland Railway
MY Madeley LEC4 149m 74ch 1930 26 June 2004 last train; 28 June 2004 official delayed from 4 May 2004 Stoke on Trent Signalling Centre (CH)
MJ Madeley Junction Demolished on last day WSJ2 156m 26ch 19 October 1969 17 November 2012 West Midlands Signalling Centre (MJ)
Maesmawr CAM 10m 57ch 1930 27 January 1997 Radyr (VR)
MR Magdalen Road 'Box moved from another (unknown) location BGK 90m 71ch 1927
Maghull SJO2 7m 24ch 1875 10 February 1994 Merseyrail (ML)
MG Magor Named Magor East to 1 December 1968. Downgraded to ground frame on renaming SWM2 151m 9ch by 1884 Newport (N)
DM Down main line automatic signals
DR Down relief line automatic signals
UM Up main line automatic signals
UR Up relief line automatic signals
Magor East See Magor
S Maidenhead Temporary code until control passed to Slough (S) MLN1 24m 24ch 8 December 1963 12 October 1974 Slough (S)
MW Maidenhead West MLN1 24m 60ch May 1891 7 December 1963 Maidenhead (S)
DM Down main line automatic signals
DR Down relief line automatic signals
UM Up main line automatic signals
UR Up relief line automatic signals
MN Maiden Newton WEY 154m 12ch 1921 15 May 1988 Dorchester South (DR)
EBX Maidstone East Code used from 8 April 1962 to 1984 SBJ 39m 72ch 8 April 1962
ME Code from 1984
MS Maidstone West PWS1 44m 54ch 4 June 1899
M Maindee Main Temporary panel SWM2 157m 26ch 16 April 1961 10 December 1962 Newport (N)
L Maindee North Temporary panel HNL1 41m 32ch 28 May 1961 10 December 1962 Newport (N)
MB Maindy Bridge Downgraded to ground frame 25 June 1966 CAM 2m 35ch September 1956 31 July 2006 Sidings removed
MF Maindy Fuel Downgraded to ground frame 25 June 1966 CAM 3m 6ch December 1933 19 March 1970 Sidings removed
Malago Vale MLN1 119m 67ch 10 April 1932 5 April 1970 Bristol (B)
Malden See New Malden
MC Malden Crossing Downgraded to gate box 10 November 1974 NMS1 16m 67ch 1868 30 January 1979 New Malden (WM)
Mallaig Junction See Fort William Junction
MC Maltby Colliery Named Maltby Colliery South to 7 August 1983 also had draw-ahead signals lettered A to D with no number BKS 9m 31ch 12 June 1911
M
B Some shunt signals at Harworth
H Signals at Harworth. Code used from March 1984, unclear whether separate 'box
R Banner repeater signals. Code used by 1987
X Draw ahead signals at Harworth
Maltby Colliery South See Maltby Colliery
M Malton Code used from 1966 YMS 21m 31ch 1873
MW Malvern Wells WAH 130m 13ch 29 December 1919
M Manchester Central MAJ 23 June 1935 4 May 1969 Line closed
AS Manchester East Signalling Control Centre Inside same building as Manchester South Former Ashburys area signals CMP2 182m 40ch 19 September 2011
BS Bredbury Sidings stop boards. Code used from 26 July 2015
GB Former Guide Bridge area signals
RJ Former Romiley Junction area signals. Code used from 2 August 2015
SE Stalybridge area signals
LR Manchester London Road At Piccadilly CMP2 ≈188m 54ch 28 August 1960 On or after 15 October 1988 Manchester Piccadilly (MP)
MN Manchester North MVE1 1m 61ch 4 August 1998 7 April 2015 Manchester Rail Operating Centre (MN)
MP Manchester Piccadilly CMP2 188m 71ch 8 October 1988
FH Farnworth temporary points, used from 2 May 2015 to 13 December 2015. Code not carried
MPX Trafford Park sidings propelling signals
Manchester Piccadilly East See Piccadilly East
BL Manchester Rail Operating Centre Blackpool (North and South) line signals HAJ 1m 42ch 14 July 2014
DN Wavertree workstation signals (former Ditton signals). Code used from 1 September 2020
LE Liverpool workstation signals (former Liverpool Edge Hill signals)
LL Liverpool workstation signals
MC Manchester Central area (formerly Castlefield interlocking) signals
MN Manchester Saltford interlocking (former Manchester North area) signals
MP Manchester Piccadilly area signals
WE Wavertree workstation signals. Code used from 2 January 2019
MS Manchester South CMP2 182m 40ch 29 March 2003
VE Manchester Victoria East MVM MVN1 0m 9ch 0m 9ch 30 March 1962 15 September 1998 Manchester North (MN)
VW Manchester Victoria West MVE1 0m 9ch 10 March 1929 8 August 1993 Manchester Victoria East (VE)
M Manea EMP 80m 5ch 1883
Mangotsfield North Junction BGL2 124m 45ch 3 November 1889 4 January 1970 planned; 27 December 1969 actual Line closed
M Manningham Junction SBF ≈207m 67ch 1889 21 October 1984 Shipley Bradford Junction (BR)
M Manningtree LTN1 59m 52ch by 1910 28 July 1984 Colchester [new] (CO)
MN Manors Code may have been used from 13 December 1937 ECM7 13 June 1943 Manors [temporary] (MN)
MN Manors [new] Also known as Manors North ECM7 9 February 1964 Newcastle (N)
MN Manors [temporary] ECM7 13 June 1943 Manors [new] (MN)
Manors North See Manors [new]
MY Manor Yard SDC ≈5m 15ch 29 June 1958 24 November 1985 hand points, etc.
MJ Mansfield Junction Closure date for Mansfield South Junction, unclear whether same 'box TSN2 ≈124m 15ch 15 October 1983 Trent (TT)
ML Mantle Lane KSL 113m 5ch 1910
MJ Manton Junction GSM1 90m 18ch 9 November 1913
MS Shunt signals
MW Manton Wood Code used from 1965 MAC3 58m 62ch 21 August 1977 Worksop East (WE)
D Down line automatic signals
ME One signal reported in 1977 notice, probably in error
ME March East Junction EMP 85m 67ch 1885 21 November 1987 delayed from 31 October 1987 March East Junction [temporary] (ME)
E Code uncertain
ME March East Junction [temporary] EMP ≈85m 68ch 21 November 1987 delayed from 31 October 1987 29 November 1987 March East Junction [reopened] (ME)
ME March East Junction [reopened] EMP 85m 67ch 29 November 1987
MH Marcheys House BWC 1m 42ch 1895
March North Junction WIG 86m 6ch 1885 21 December 1975 Whitemoor Junction (WJ)
MS March South Junction EMP 85m 35ch 14 March 1928
MW March West Junction EMP 86m 17ch 1886 29 November 1987 March East Junction [reopened] (ME)
MW Marchwood Upgraded from ground frame 28 November 1943 TTF 86m 10ch 20 July 1925
RE Marden XTD 39m 29ch ≈1884 30 July 1967 Staplehurst (SE)
A Automatic signals
Margam East See Margam Middle
HY Margam Hump Yard One source has closure on 3 December 1967 OVE 0m 53ch 15 May 1949 1 November 1987 Port Talbot (PT)
MY Code used?
MD Margam Middle Named Margam East to 17 December 1950 SWM2 201m 22ch 1911 20 October 1963 Port Talbot (PT)
MM Margam Moors SWM2 199m 2ch c July 1912 20 October 1963 Port Talbot (PT)
GE Margate Named Margate A to 19 July 1959 VIR 73m 53ch 1 July 1913 24 December 2011 East Kent Signalling Centre (EK)
A Automatic signals
Margate A See Margate
MB Markham Bunker Also had draw-ahead signals lettered A to E with no number MCB 19 July 1970 (?) Line closed
M Markinch Junction Code used from 1980 ECN2 ≈33m 16ch ? 14 July 1980 Edinburgh (ER)
MT Marks Tey Code used from 3 December 1961 LTN1 46m 67ch ≈1890 18 October 1997 Liverpool Street [new] (L)
D Down line automatic signals
U Up line automatic signals
M Marsden MVL3 18m 54ch 24 April 1993 Huddersfield (HU)
MM Marshall Meadows ECM7 68m 2ch 25 May 1921 9 December 1961 Tweedmouth (T)
MB Marsh Brook SHL 15m 29ch 1872 Wales Rail Operating Centre (NS) (planned)
MF Marshfield SWM2 163m 62ch 1897? 4 June 1966 Cardiff (C)
MG Marshgate Goods Code probably used from 1949 DOW 0m 23ch 1873 8 July 1979 Doncaster (D)
M Marsh Junction Code used from 26 September 1993 MAC3 107m 77ch 1908 30 December 2015 York Rail Operating Centre (CB, MB)
MJ
Marsh Junction [Bristol] Demolished 1993 BRL 0m 22ch 2 March 1959 18 July 1970 Bristol (B)
ML Marsh Lane HUL4 19m 58ch 30 April 1967 Leeds (L)
ML Marsh Lane Downgraded to gate box 28 June 1936 BML1 10m 76ch 30 September 1906 23 May 1937 Surbiton (WN)
ML Marsh Lane Junction Code used by 1986 6 November 1988 Bootle Junction [new] (BJ)
M Marshmoor ECM1 ≈15m 71ch 4 March 1886 17 November 1972 Potters Bar [new] (PB)
R Repeater signals
M Marston Moor Downgraded to gate box 4 June 1972: line controlled by Hammerton (H) HAY1 6m 7ch 1910
MV Marston Vale [Ridgmont] BBM 6m 60ch 6 September 2004
MM Martin Mill BME2 95m 5ch 7 October 1934 12 April 1998 Deal (EBZ)
MP Maryhill Park Junction Burnt down 14 October 1980, replacement 'box built 1984 but never opened MRL1 4m 40ch 20 October 1874 19 October 1980 Yoker (YS)
M Marylebone Downgraded to shunt frame 22 September 1990 MCJ1 205m 52ch 9 October 1967 1991 Marylebone [new] (ME)
ME Reported, possibly not carried
D Down direction automatic signals
U Up direction automatic signals
ME Marylebone [new] MCJ1 205m 77ch 23 April 1990
OB Oxford to Bletchley section. Code used from 2016
MS Maryport Station Believed code not carried CBC3 0m 21ch 1933
A Draw ahead signals. Codes used from 27 January 1980
B Draw ahead signals. Codes used from 27 January 1980
C Draw ahead signals. Codes used from 27 January 1980
D Draw ahead signals. Codes used from 27 January 1980
M Masborough Station North Junction Code used from 1965 TJC3 162m 10ch 29 July 1979 Sheffield (S)
MN
MS Masborough Station South Junction Code used from 1965 TJC3 163m 68ch 29 July 1979 Sheffield (S)
MA Mauchline Code used 2002 to 2003. Named Mauchline No 1 to 3 May 1970 GSW 43m 2ch 1874
MM Code from 2003
Mauchline No 1 See Mauchline
MF Maud Foster Downgraded to gate box 12 April 1981: line controlled by Boston West Street Junction (WS) GRS3 108m 66ch October 1877 30 June 1985 Grand Sluice (GS)
M Meadowhall SMC 3m 20ch? 10 April 1983 Shepcote Lane Junction (SL)
MD Meaford Crossing CMD2 27m 17ch 1880 25 May 2002 Stoke on Trent Signalling Centre (SOT)
M Medge Hall Downgraded to gate box 15 October 1972: line controlled by Doncaster (D). Believed code not carried DOW 13m 3ch 1886
G Meldon Quarry [train loading equipment control panel] Draw ahead signals. Code used from 14 July 1980 DAC ≈199m 6ch Quarry closed
B Melkridge Opencast Disposal Point NEC2 ≈37m 37ch
M Mellis Both codes reported in signalling notices: MS looks more likely to have been carried LTN1 91m 40ch 1883 14 June 1986 Colchester [new] (CO)
MS
R Melmerby South Repeater signals LEN1 Line closed
ML Melton Lane Code used from 27 July 1980 HUL1 8m 41ch 1921 23 November 2018 last train; 26 November 2018 official delayed from 3 April 2018 York Rail Operating Centre (GH)
M Some signals
MM Melton Station GSM2 105m 27ch 1942
R Repeater signals
R1 Off indicators
R2 Off indicators
X Draw ahead signals
EO Meopham VIR 26m 0ch ≈1876 27 November 1965 Rochester (ER)
MN Merllyn Level Crossing Ground Frame DJP 124m 28ch Machynlleth (MH)
ML Merseyrail HXS2 35m 0ch February 1994
Metheringham See Blankney
M Methley Junction MEW2 TJC3 1m 12ch 187m 37ch 1891 20 September 1997 Castleford (CD)
MJ
B Metropolitan Junction XTD 1m 39ch 25 November 1900 15 April 1976 London Bridge (L)
M Mexborough Named Mexborough No 2 to 26 July 1970. Code used from renaming PED5 15m 65ch 1931 3 August 1980 Sheffield (S)
M2 Code used from 1966 to 26 July 1970
M1 Mexborough No 1 Code used from 1965 PED4 15m 41ch 18 February 1900 13 December 1965 Mexborough No 2 (M2)
Mexborough No 2 See Mexborough
M3 Mexborough No 3 Code used from 1966 WME 9m 73ch ≈1920 26 July 1970 Mexborough (M)
MW Mexborough West Code used from 1965 PED4 14m 72ch 1925 7 July 1965 Mexborough No 3 (M3)
M Micklefield HUL4 ≈10m 63ch Peckfield (P)
MT Mickle Trafford CDM2 CHW1 35m 35ch 2m 59ch 1969
ML Code on signalling plan, believed never carried
MJ Midcalder Junction Code used from 1981 ECA2 89m 63ch 1969 23 November 1981 Edinburgh (EJ)
M Middlesbrough Named Middlesbrough West to September 1977. Code used from renaming DSN2 14m 71ch 1877
MW Code used to September 1977
R Middlesbrough West distant signals
ME Middlesbrough East DSN2 9 November 1969 Middlesbrough (M)
Middlesbrough West See Middlesbrough
MS Middle Sidings Ground Frame MLN1 10 September 1966 Old Oak Common (OO)
M Middlestown Junction Near Healey Mills Route closed?
MH Midge Hall FCO 22m 79ch 5 November 1972
ME Mile End LTN1 30 January 1949 13 October 1968 Liverpool Street (L)
DE Down electric line automatic signals
DM Down main line automatic signals
UE Up electric line automatic signals
UM Up main line automatic signals
MG Miles Platting Station Junction Unclear whether code applied to this 'box or another MVM 1m 30ch 1890 15 September 1998 Manchester North (MN)
M Milford Named Milford South to 11 September 1971 (but still referred to as such 20 May 1973) NOC 14m 71ch 1957
MS
MB Milford & Brockton LEC3 3 February 1935? 19 May 1962 Stafford No 4 (SD4)
Milford South See Milford
WFM Milford [Surrey] WPH1 36m 24ch ≈1876 9 December 1973 Farncombe (WZ)
S Milford West Sidings Shunters Cabin 1 June 1980
MK Millbrook [Beds] Believed code not carried BBM 10m 2ch ≈1870 23 July 2004 last train; 6 September 2004 official Marston Vale (MV)
MC Millbrook Church Lane Unclear whether details are correct, it is known that MC signals were used near Millbrook BML1 Eastleigh [new] (E)
Millbrook Dock Gates MIS 80m 32ch 2 June 1935 Line closed?
MB Millbrook [Hants] BML1 80m 19ch 2 June 1935 8 November 1981 Eastleigh [new] (E)
M Millerhill Code used from 1962 NDE1 6m 4ch 1873 6 May 1962 Millerhill [panel] (M)
M Millerhill [panel] NDE1 5m 42ch 6 May 1962 11 December 1988 Millerhill [new] (M)
M Millerhill [new] NDE1 5m 2ch 11 December 1988 25 November 2012 Edinburgh (EM)
MW Waverley route signals. Code seen on proposal plans, never used
MD Millerhill Depot NDE1 ≈5m 7ch 12 November 2017
H Millerhill Down [Hump] Yard Control Tower NDE1 ≈5m 5ch 8 April 1963 8 April 1981
H Millerhill Up [Hump] Yard Control Tower NDE1 16 June 1962 1969 Yard closed
MG Mill Green SPD1 44m 73ch 6 March 1882 11 August 2014 delayed from 3 March 2014 Lincoln Control Centre (WS)
M Millhouses & Eccleshall TJC1 20 January 1973 Sheffield (S)
M Mill Lane Junction MRB 39m 79ch 1884 20 October 2018 last train; 23 October 2018 official York Rail Operating Centre (HB, MM)
ML Last signal before York [IECC] (L) signals. Unclear whether this signal is jointly controlled
MR Banner repeater signals. Both codes shown on same diagram
RM Banner repeater signals. Both codes shown on same diagram
MM Millom CBC1 45m 7ch 1917
Milner Royd See Milner Royd Junction
MR Milner Royd Junction Also known as Milner Royd MVN2 29m 22ch 1878 20 October 2018 last train; 23 October 2018 official York Rail Operating Centre (MM)
M Unclear whether code carried
M Milngavie Code used from 1959 MGE 9m 8ch 21 January 1900 21 October 1990 Yoker (YH)
Milngavie Junction See Westerton
MJ Milton Junction SCQ2 ≈0m 5ch 1880 20 May 1987 Stoke on Trent [panel] (SE)
M Milton Village Gate box: line controlled by Brampton Fell (BF) NEC2 48m 60ch 1893
MX Minety Gate box: line controlled by Swindon (SN) SWM1 86m 73ch (16 June)? 1968 4 August 2014 last train; 23 August 2014 official Thames Valley Signalling Centre (SW)
EBE Minster ACR 81m 74ch 23 June 1929
A Automatic signals
M Mirfield Named Mirfield Junction No 3 to 2 May 1970. Code used from renaming MVN2 38m 49ch ? 18 October 1970 Healey Mills (HM)
M3 Code used when named Mirfield Junction No 3, probably carried from 1963
D Down line automatic signals when named Mirfield Junction No 3
M1 Mirfield Junction No 1 Code presumed, probably not carried MVN2 38m 7ch ? 2 May 1970 Healey Mills (HM)
M2 Mirfield Junction No 2 Code referenced in signalling notice, probably not carried MVN2 38m 21ch ? 2 May 1970 Healey Mills (HM)
Mirfield Junction No 3 See Mirfield
M4 Mirfield Junction No 4 Code presumed, probably not carried ? May 1970? Healey Mills (HM)
M5 Mirfield Junction No 5 Code referenced in signalling notice, probably not carried MVN2 ≈39m 30ch ? May 1970? Healey Mills (HM)
MI Mistley MAH 61m 17ch ≈1882 29 September 1985 Colchester [new] (CO)
MJ Mitcham Junction Code used from 1969 CMJ 3m 9ch 20 May 1928 23 May 1982 Victoria Signalling Centre (VC)
RC Code used to 1969
CA Automatic signals
MM Mitchells Main PED3 10m 12ch 1875 17 November 1985 line closed
MB Mitre Bridge Junction WLL ≈5m 70ch 14 October 1990 Willesden PSB (WN)
MY Mobberley CDM2 11m 75ch 1886
MW Moira West Junction KSL 120m 67ch 14 June 1896 23 November 1986 Moira West Junction [temporary] (MW)
MW Moira West Junction [temporary] KSL 120m 67ch 23 November 1986 16 December 1986 Moira West Junction [reopened] (MW)
MW Moira West Junction [reopened] KSL 120m 67ch 16 December 1986
MJ Mold Junction Possibly replaced by new 'box in 1946. Named Mold Junction No 1 to 26 February 1978 CNH3 182m 29ch 1902 early on 23 January 2005 Chester PSB (CR)
Mold Junction No 1 See Mold Junction
MN Monkseaton TMB 7m 71ch 10 September 1979 Line transferred to Metro
D Down direction automatic signals
U Up direction automatic signals
MS Monks Siding SDJ2 11m 71ch 1875
MK Monktonhall Junction ECM8 6m 6ch 15 December 1912 1 August 1977 Edinburgh (EM)
MW Monkwearmouth Code used from 1965. Out of use by 1997 LEN3 90m 26ch ≈1876 11 January 2002 Tyneside (T)
MN Montrose North Code used from 2002 ECN4 30m 69ch 1 March 1881
MS Montrose South Code used from 2002 ECN4 30m 37ch 1 March 1881 2 February 2010 delayed from 28 January 2008 Montrose North (MN)
M Moorhouse Junction DOL1 163m 26ch 3 August 1907 21 November 1970 South Kirkby Junction (SK)
M Moorthorpe Named Moorthorpe South to ≈22 April 1984 SMJ2 11m 63ch 1908 31 May 2011 York [IECC] (L)
MS Code when named Moorthorpe South
U Up direction distant signals
FC Frickley Colliery signals
Moorthorpe South See Moorthorpe
Moortown NOB3 19m 34ch July 1890 15 April 1989 Holton le Moor (H)
ME Morecambe Named Morecambe Promenade to 16 November 1967 MSM 2m 10ch 1907 6 March 1994 Bare Lane (BL)
Morecambe Promenade See Morecambe
Moreton CWK3 6m 23ch 1932 18 September 1994 Merseyrail (ML)
MC Moreton Cutting MLN1 51m 38ch 1907 17 May 1965 Reading (R)
M Moreton Cutting Ground Frames Unclear whether code used MLN1 Swindon B (SB)
MM Moreton In Marsh OWW 91m 56ch 1883
M Unclear whether code used
ML Moreton On Lugg SHL 46m 65ch 24 October 1943 Wales Rail Operating Centre (NS) (planned)
M Code shown in 1991 notice
ML Morlais Junction LLA 3m 57ch 1913 7 July 1973 Port Talbot (PT)
Morley See Morley Low
M Morley Low 'Morley' carried on 'box MDL1 38m 26ch 1960? 10 August 1985 Batley (B)
ML Code used by 1980
RM Banner repeater signals
U Up line automatic signals
M Morningside Road SUB2 2m 7ch 31 October 1884 26 June 1977 Edinburgh (ES)
M Morpeth Code used by 1963 ECM7 21 October 1978 Morpeth [new] (M)
D Down line automatic signals
GF Ground frame controlled signals
R Repeater signals
RU Repeater to up line automatic signals
U Up line automatic signals
M Morpeth [new] ECM7 16m 63ch 21 October 1978 23 February 1991 Morpeth [temporary] (M)
M Morpeth [temporary] ECM7 16m 63ch 23 February 1991 14 July 1991 Morpeth [reopened] (M)
M Morpeth [reopened] 'New' 'box, reopened after refitting ECM7 16m 63ch 14 July 1991
WBQ Mortlake Downgraded to gate box 2 June 1974 RDG1 8m 15ch by 1892 19 December 1976 Barnes (WBO)
M Moss Downgraded to gate box 22 March 1970: up line controlled by Shaftholme (SH), down line controlled by Brayton (BN) ECM2 163m 2ch 1873 18 April 2015 Doncaster (D)
Mossend EWS Shunters SCM2 91m 60ch 8 May 2003
Mossend Junction See Mossend No 4
MD Mossend No 4 Named Mossend Junction, then named Mossend West to 26 October 1902. Code used from 1973 EGS1 3m 3ch 13 December 1892 4 September 1973 delayed from 12 August 1973 Motherwell (M)
Mossend West See Mossend No 4
MN Mostyn Named Mostyn No 1 to 1943. Used only as required from 10 November 2008 CNH3 199m 12ch July 1902 8 January 2017 last train; 9 January 2017 official Talacre (TE)
Mostyn No 1 See Mostyn
M Motherwell Motherwell interlocking WCM2 88m 78ch 17 December 1972 26 December 2019 West Of Scotland Signalling Centre (GMC)
MB Burnhouse interlocking. Code used from 6 May 2003
MC Carstairs (and south) interlockings
MG Gartsherrie interlocking. Code used from 1999
MH Haughhead interlocking. Code used from 4 July 2005
MR Banner repeater signals
MS Mossend South interlocking. Code used from 6 May 2003
MY Mossend Yard interlocking. Code used from 6 May 2003
R Banner repeater signals
MC Motherwell Colliery Downgraded to gate box 17 December 1972 WCM2 89m 78ch 1 November 1893 10 June 1984 Motherwell (M)
M Unclear whether code carried
WT Motspur Park Named Blue House Crossing to 23 September 1929. Code used from 27 February 1966 RPE 9m 52ch 1900 22 July 1990 Wimbledon (W)
WA Automatic signals
EBM Mottingham Named Eltham to 1 October 1927 HDR 11 June 1894 14 September 1969 London Bridge (L)
M2 Mottram Also known as Mottram Yard No 2. Named Mottram No 2 to 15 October 1978 HAJ 11m 32ch 31 March 1935 4 April 1982 Dinting (DG)
M1 Mottram No 1 Also known as Mottram Yard No 1 HAJ 10m 23ch 2 June 1935 14 October 1978 Mottram No 2 (M2)
Mottram No 2 See Mottram
Mottram Yard No 1 See Mottram No 1
Mottram Yard No 2 See Mottram
MH Mouldsworth CDM2 31m 5ch 17 June 1894 22 May 2006 Mickle Trafford (MT)
MF Mountfield Siding Ground frame: line controlled by Robertsbridge (RB) TTH 51m 78ch 16 March 1975
MG Mount Gould Junction SUT1 244m 39ch 1891 10 November 1973 Plymouth (P)
MT Mount Pleasant Crossing BML1 77m 64ch 4 May 1902 11 October 1981 Eastleigh [new] (E)
MC Mow Cop CMD1 11m 30ch by 1879 15 May 2002 last train; 27 May 2002 official Stoke on Trent Signalling Centre (SOT)
M Mucking Crossing Downgraded to gate box 19 August 1973: line controlled by Low Street (L) TLL ≈26m 40ch Upminster IECC (UR)
M Muckingford Downgraded to gate box 19 August 1973: line controlled by Low Street (L) TLL ≈26m 13ch Upminster IECC (UR)
ME Muirend Code used from 1961. Open only as required from 23 July 1961 NNH 101m 48ch 26 April 1903 16 November 1980 Cathcart (C)
MJ Muirhouse Junction Code used from 7 August 1961. Some automatic signals known with A, B or C suffix CTC 5m 19ch 7 August 1961 18 September 1973 Glasgow Central (G)
D Murrow West Down direction automatic signals MSG3 31m 1ch 1881 9 October 1941 Murrow West [temporary] (MW)
MW Murrow West [new] MSG3 31m 1ch 26 November 1950 27 November 1982 Line closed
MW Murrow West [temporary] Named Murrow to 27 September 1948 MSG3 31m 1ch 4 November 1941 26 November 1950 Murrow West [new] (MW)
B Murton Colliery HEM? Sidings closed
C