Editing Great Eastern Main Line (section)

==== Feeding arrangements ====
The majority of the GEML network is electrified using the [[Railway electrification in Great Britain#Feeding Arrangements (Classic)|'classic' feeding arrangement]] connected to the 132kV distribution grid all controlled by [[UK Power Networks]]. In accordance with the [[Crossrail]] project, [[Railway electrification in Great Britain#Feeding Arrangements (Autotransformer)|autotransformer feeding]] was fitted between the new autotransformer feeder station (ATFS) at Pudding Mill Lane and Gidea Park. Pudding Mill Lane ATFS also feeds the Crossrail core from that point to the Westbourne Park tunnel portal and towards Abbey Wood.<ref>{{Cite web |title=East meets west |url=https://www.railtechnologymagazine.com/Comment/east-meets-west |access-date=2025-02-21 |website=www.railtechnologymagazine.com}}</ref> This entirely replaced Crowlands classic feeder station (located between [[Chadwell Heath]] and [[Romford railway station|Romford]]) and significantly reduced the load of the Bow Junction classic feeder station. The feeder station is connected to the [[National Grid (Great Britain)|National Grid]] 400kV transmission substation also named Pudding Mill Lane.

The line between Gidea Park and Shenfield is fitted out to be converted to autotransformer feeding in the near future with a sectioning autotransformer station (SATS) already completed at Shenfield in 2018.<ref>{{Cite web |title=Shenfield SATS sub-station |url=https://vgcgroup.co.uk/case-studies/shenfield-sats-sub-stations/ |access-date=2025-02-22 |website=VGC Group }}</ref> Autotransformer feeding is also due to be extended as far as [[Beaulieu Park railway station|Beulieu Park]] as a new ATFS is being constructed just north of the station at the same site as the Springfield classic feeder station.<ref>{{Cite web |title=Great Eastern Main Line Power Supply Upgrade Beaulieu Feeder Station (GRIP 2 to 8) |url=https://www.amey.co.uk/media/news/2020/february/great-eastern-main-line-power-supply-upgrade-beaulieu-feeder-station-grip-2-to-8/ |access-date=2025-02-22 |website=Amey }}</ref>

The original 1.5kV DC system of 1949 used traction substations at Bethnal Green, Stratford, Chadwell Heath, Gidea Park, and Shenfield all supplied by 33kV 3 phase AC distribution ring owned and operated by the railway. The 33kV ring was itself supplied by the utility grid at Chadwell Heath and Crosswall (near Fenchurch Street).<ref name=":4">{{Cite book |last=British Railways—Eastern Region (Great Eastern Line) |title=Liverpool Street and Fenchurch Street to Chelmsford and Southend (Victoria) Electrified Lines Working Instructions |publisher=(internal) |year=1956 |ref=BR29818}}</ref> Beyond Shenfield, the DC system installed in 1956 to Chelmsford and Southend Victoria did not use the railway distribution lines but were connected directly to the public utility grid at 33kV.<ref name=":5">{{Cite journal |last=Baker |first=John |date=Oct 1992 |title=GE Section Overhead Electrification 1935-1969, Part 3 |journal=Great Eastern Journal |volume=72 |pages=27}}</ref> Between Liverpool Street and Shenfield, the DC substations were significantly altered but retained for the conversion to 6.25kV in 1960 but were unsuitable for the further upgrades to 25kV. So too were the 33kV distribution lines which were reinforced by replacing the Crosswall grid connection with a stronger one at Bethnal Green. However after 1960, the distribution lines no longer powered Shenfield substation as a new feeder station was built that could supply both 6.25kV southwards and on the Southend line and 25kV for the line north to Chelmsford and for the future upgrade.<ref name=":2" />

From 1976 to 1980 the 6.25kV lines between Liverpool Street and Southend Victoria were upgraded to 25kV which required entirely new grid connections and substations. New feeder stations were installed at Crowlands and at Bow Junction. The substation at Gidea Park became the MPTSC between Shenfield and Crowlands, and a brand new MPTSC was installed at Manor Park to separate Crowlands and Bow Junction feeder stations. Bow Junction feeder station also supplied the WAML up to a new MPTSC at Hackney Downs by way of a new Spitalfields TSC around Bethnal Green junction.<ref name=":6">{{Cite web |title=Anglia / Romford ECR {{!}} Signalling Photos |url=https://photos.signalling.org/index?/category/235-romford_ecr |access-date=2025-02-22 |website=photos.signalling.org}}</ref>
{| class="wikitable"
|+List of traction substations on the Great Eastern Main Line<ref name=":4" /><ref name=":5" /><ref name=":6" /><ref>{{Cite book |last=British Railways—Eastern Region (Great Eastern Line) |title=Working Instructions for Electrified Lines |publisher=(internal) |year=1960}}</ref><ref>{{Cite book |last=British Railways—Eastern Region (London, Tilbury and Southend Line) |title=Working Instructions for Electrified Lines |publisher=(internal) |publication-date=1961 |ref=BR31248}}</ref><ref>{{Cite book |last=British Railways |title=Working Instructions for A.C. Electrified Lines |publisher=(internal) |year=1975 |ref=BR29987}}</ref><ref>{{Cite journal |last=Ministry of Transport (Railway Accidents) |year=1962 |title=Final report on the Accidents and Failures which occurred in Multiple Unit Electric Trains in the Scottish Region and Eastern Region of British Railways |journal=London: HM Stationery Office}}</ref>
!Mileage{{Efn|1=Measured in miles and chains (80 chains = 1 mile)}}
!Substation
![[Railway electrification in Great Britain#Feeding Arrangements (Classic)|Type]]
!In use
!Neutral Section
!Grid Connection
!Notes
|-
|0m 0c
| colspan="6" |[London Liverpool Street station: datum point for the line]
|-
|0m 30c
|''Liverpool Street''
|''TSC{{Efn|Technically speaking, a TSC on a DC railway should be referred to as a Track Paralleling Hut (TPH), they are functionally similar. However, this table will call them TSC for simplicity with terminology for AC systems. In addition, the original documentation for the DC system used the term TSC.}}''
|''1949–1980''
|''no''
|''n/a''
|Converted in 1960 from 1.5kV DC to 6.25kV AC
|-
|01m 14c
|Spitalfields
|TSC
|since 1980
|no
|n/a
|Allows Bow Junction "A" to feed the WAML that splits at Bethnal Green. Replaced Liverpool Street TSC
|-
|01m 22c
|''Bethnal Green''
|''FS''
|''1949–1980''
|''yes (from 1960)''
|''Railway owned 33kV ring''
|Converted in 1960 from 1.5kV DC to 6.25kV AC. Substation also fed WAML from 1960.
|-
|02m 68c
|''Bow Junction''
|''TSC''
|1949–1980
|''no''
|''n/a''
|Converted in 1960 from 1.5kV DC to 6.25kV AC
|-
|03m 15c
|Bow Junction
|FS
|since 1980
|yes{{Efn|Neutral sections at Bow FS were moved to 2m 70c in 1995, and to 2m 68c in 2015.
03m 15c represents where the substation is approximately located}} 
|[[UK Power Networks|UKPN]] 132kV underground power line
(Hackney Supergrid 132 to Bow 132)<ref>{{Cite web |last=UK Power Networks |year=2014 |title=LPN Regional Development Plan (North London) |url=https://library.ukpowernetworks.co.uk/Library/GetPdf?pdfUrl=Asset_Management_Documents%2FRegional_Development_Plans%2FLPN%2FLPN_RDP_North_London_Islington_Hackney.pdf |format=pdf}}</ref>
|Dual FS with "A" and "B" sides. Installed for 25kV upgrade. Replaced Bethnal Green and Stratford FSs. Since 2022, the "B" side no longer feeds GEML but does supply [[North London line|North London Line]] and [[Lea Valley lines#Route and services|Temple Mills Branch]] via ducting to the Stratford area.
|-
|03m 31c
|Pudding Mill Lane
|ATFS
|since 2022
|yes
|Adjacent [[National Grid (Great Britain)|National Grid]] Pudding Mill Lane 400kV transmission substation
|Dual ATFS. "A" side powers Crossrail Central Operating Section, "B" side powers GEML replacing Bow Junction "B" FS.
|-
|04m 55c
|''Stratford''
|''FS''
|''1949–1980''
|''yes (from 1960)''
|''Railway owned 33kV ring''
|Converted in 1960 from 1.5kV DC to 6.25kV AC
|-
|05m 71c
|Manor Park
|SATS
|since 1980
|yes
|''n/a''
|Installed for 25kV upgrade. Acted as an MPTSC between Bow Junction "B" FS and Crowlands "A" FS until Pudding Mill Lane ATFS replaced both in 2022. Neutral section still in situ so this substation may still be in use in some.
|-
|08m 20c
|Ilford
|SATS
|since 1949
|no
|''n/a''
|Installed originally as a TSC from 1949, converted to 6.25kV in 1960, to 25kV in 1980, and finally converted to a SATS by 2022.
|-
|10m 49c
|''Chadwell Heath''
|''FS''
|''1949–1980''
|''yes (from 1960)''
|''Railway owned 33kV ring''
|Converted in 1960 from 1.5kV DC to 6.25kV AC. Chadwell Heath was the location of the main grid connection for the railway's 33kV ring.
|-
|11m 24c
|Crowlands
|SATS
|since 1980
|yes
|(''1980–2022'') UKPN 132kV underground power line 
(Barking 132kV to Crowlands Grid)<ref name=":3">{{Cite web |last=UK Power Networks |title=EPN Regional Development Plan: Barking, Warley & West Thurrock |url=https://library.ukpowernetworks.co.uk/Library/GetPdf?pdfUrl=Asset_Management_Documents%2FRegional_Development_Plans%2FEPN%2FEPN_RDP_Warley_Barking_West_Thurrock_GSP.pdf |format=pdf}}</ref>
|Originally Dual FS with "A" and "B" sides. Installed for 25kV upgrade. Replaced Chadwell Heath FS and Gidea Park as an FS. The substation may have become a SATS from 2022 since the neutral section is still in situ.
|-
|14m 45c
|Gidea Park
|MPATS/MPTSC
|since 1949
|yes (from 1960)
|(1949–1980) Railway owned 33kV ring
(since 1980) n/a
|Installed originally as an FS from 1949, converted to 6.25kV in 1960. Converted into a MPTSC between Crowlands "B" and Shenfield "A" in 1980 and finally converted to a MPATS by 2022.
|-
|17m 01c
|''Brook Street''
|''MPTSC''
|''1949–1976''
|''yes (from 1960)''
|''n/a''
|Originally as 1.5kV TSC, converted to 6.25kV MPTSC in 1960, substation removed in 1976.
|-
|19m 70c
|''Shenfield [DC]''
|''FS (DC)''
|''1949–1960''
|''no''
|''Railway-owned 33kV ring''
|Only ever a 1.5kV DC feeder station. Replaced by the new Shenfield FS with 132kV grid connection.
|-
|20m 72c
|Shenfield [new]
|FS
|since 1960
|yes
|UKPN 132kV underground power line
(Warley 132kV Grid to Shenfield Grid)<ref name=":3" />
|Dual FS, originally capable of 6.25kV and 25kV operation until 1980 when it fed all lines at 25kV.
Since Springfield FS was introduced, normally only of two supplies is in use for the section Gidea Park to Shenfield. Substation is configured to feed the Southend line if needed.
The site has been added to with a SATS since 2022 that is not yet in use.
|-
|23m 40c
|''Ingatestone''
|''TSC''
|''1956–1960''
|''no''
|''n/a''
|1.5kV DC TSC, removed when line was de-energised in 1960 for conversion to 25kV AC by 1961
|-
|27m 15c
|''Hylands''
|''FS (DC)''
|''1956–1960''
|''no''
|''unknown''
|1.5kV DC FS, removed when line was de-energised in 1960 for conversion to 25kV AC by 1961
|-
|29m 40
|Chelmsford
|TSC
|since 1961
|no
|n/a
|Installed 1961 for the 25kV system
|-
|33m 06c
|Springfield
|FS
|since 1993
|yes
|UKPN 132kV overhead powerline
(Rayleigh Main 132kV to Braintree 132kV)<ref>{{Cite web |last=UK Power Networks |year=2014 |title=Braintree — Rayleigh (EPN) |url=https://library.ukpowernetworks.co.uk/Library/GetPdf?pdfUrl=Asset_Management_Documents%2FRegional_Development_Plans%2FEPN%2FEPN_RDP_Rayleigh_Braintree_Group.pdf |format=pdf}}</ref>
|Dual FS installed ~30 years after this section was originally electrified.
Due to soon become an ATFS
|-
|38m 12c
|Witham
|TSC/MPTSC
|since 1962
|yes
| rowspan="2" |n/a
|Originally installed as an MPTSC between Shenfield and Colchester FSs. Since Springfield FS was introduced, Witham is probably switched through in normal operation.
|-
|43m 50c
|Hill House
|MPTSC (?)
|since 1962
|yes (since 2011)
|Originally installed as a TSC on the Colchester supply in 1962. A neutral section was added in 2011 likely to separate the Springfield "B" and (new) Hythe "A" supplies. Unknown if any switching ability exists at this substation.
|-
|52m 21c
|Colchester
|MPTSC
|since 1959
|yes
|1959–1993: yes (unknown)
1993–present: no
|Originally installed as a dual FS. B side supplying the Clacton line (from 1959) and A side feeding the mainline to Witham in 1962. Colchester likely ceased being an FS in 1993 when Springfield FS on the mainline and Hythe FS (by 1989) on the Clacton line were installed.
Currently it is a three way MPTSC distributing the incoming Hythe FS "A" supply to the mainline south to Hill House as well as terminating the supply from Manningtree FS to the north.
|-
|59m 47c
|Manningtree
|FS 
| rowspan="2" |since 1985
|yes
|UKPN 132kV overhead powerline (Cliff Quay grid to Lawford Grid)<ref>{{Cite web |last=UK Power Networks |date=2014 |title=EPN Regional Development Plan: Bramford – Rayleigh 132kV group network |url=https://library.ukpowernetworks.co.uk/Library/GetPdf?pdfUrl=Asset_Management_Documents%2FRegional_Development_Plans%2FEPN%2FEPN_RDP_Rayleigh_Bramford_Group.pdf |format=pdf}}</ref>
|The first single supply (tee feeding) FS on GEML only feeding southwards to Colchester. The substation also supplies the entirety of the Harwich line.
|-
|69m 42c
|Ipswich
|TSC
|no
|n/a
|
|-
|79m 10c
|Stowmarket
|FS
|since 1986
|yes
|UKPN 132kV overhead powerline
(Bramford Grid to Bury [st Edmunds] Grid)<ref>{{Cite web |last=UK Power Networks |date=2014 |title=EPN Regional Development Plan: Bramford Grid - West Suffolk 33kV Network |url=https://library.ukpowernetworks.co.uk/Library/GetPdf?pdfUrl=Asset_Management_Documents%2FRegional_Development_Plans%2FEPN%2FEPN_RDP_Bramford_GSP_West.pdf |format=pdf}}</ref>
|Dual supply FS
|-
|85m 24c
|Cow Green
|TSC
| rowspan="5" |since 1987
|no
| rowspan="4" |n/a
|
|-
|91m 34c
|Mellis
|TSC
|no
|
|-
|98m 76c
|Hales Street
|MPTSC
|yes
|
|-
|106m 63c
|Flordon
|TSC
|no
|
|-
|123m 38c
|Norwich 
|FS
|no
|UKPN 25kV underground powerline to nereby Thorpe 132kV Grid
|Single supply FS
|-
|124m 09c
| colspan="6" |[Norwich Station, end of line]
|}
{{noteslist}}