Railway electrification in Great Britain
- 1 History
- 2 Proposed developments
- 3 Existing systems – overhead line (OHL)
- 4 Existing systems - third and fourth rails
- 5 Obsolete systems
- 5.1 6,600 V, 25 Hz AC, overhead
- 5.2 6,250 V 50 Hz AC, overhead
- 5.3 3,500 V DC, overhead
- 5.4 1,500 V DC, overhead (historic)
- 5.5 1,200 V DC, third rail (side-contact)
- 5.6 650 V DC, overhead
- 5.7 600 V DC, third rail
- 5.8 550 V DC, overhead
- 5.9 525 V DC, third rail
- 5.10 500 V DC, overhead
- 5.11 500 V DC, third rail
- 6 Facts and figures
- 7 See also
- 8 References
- 9 Further reading
- 10 External links
Railway electrification in Great Britain began during the late 19th century. A range of voltages has been used, employing both overhead lines and third rails; the most common are 25 kV AC using overhead lines and the 750 V DC third-rail system in southeast England and on Merseyrail. 40 percent—3,062 miles (4,928 km)—of the British rail network is electrified, and 60 percent of all rail journeys are by electric traction (locomotives and multiple units). 66 percent of the electrified network uses 25 kV AC overhead, and 36 percent 660/750 V DC third-rail.when?citation needed Subways, light rail and tram systems employ a variety of other systems.
In 1921 a government committee chose 1,500 V DC overhead to be the national standard,1 but little implementation followed and many different systems co-existed.
After World War II and the nationalisation of the railways in 1948, British Railways expanded electrification at both 1,500 V DC overhead and 660/750V third rail. In 1956, British Railways adopted 25 kV AC overhead as standard for all projects outside logical extensions of third-rail systems.2
The 25 kV AC network has continued to expand slowly, and large areas of the country outside London are not electrified. In 2007 the government's preferred option was to use diesel trains running on biodiesel, its white paper Delivering a Sustainable Railway,3 ruling out large-scale railway electrification for the following five years.
In May 2009 Network Rail launched a consultation on large-scale electrification, to potentially include the Great Western Main Line and Midland Main Line and smaller "in-fill" schemes. Key benefits cited were that electric trains are faster, more reliable and cause less track wear than diesel trains.4 Since then, electrification of the Great Western Main Line has been approved; trains are planned to run to Bristol from 2016 and Cardiff from 2017.5
In Scotland, where transport is devolved to the Scottish Government, Transport Scotland is extending electrification, for example, on the Airdrie-Bathgate Rail Link. This is part of a larger plan that sees many major routes in central Scotland electrified, including the main Edinburgh-Glasgow Queen St route.
In June 2011, Peter Dearman of Network Rail suggested that the third-rail network will need to be converted into overhead lines. He stated, "Although the top speed is 100mph, the trains cannot go over 80mph well and 25% of power is lost from heat". Agreeing that conversion would be expensive, he said that the third-rail network is at the limit of its power capability, especially as trains become more advanced in technology.6 The July 2012 Department for Transport High Level Output Specification for Network Rail Control Period 5 includes the conversion of the South West Main Line between Southampton and Basingstoke from 750 V DC third rail to 25 kV AC overhead as part of a scheme to improve rail freight capacity from Southampton Port. This conversion is a pilot scheme to develop a business case for full conversion of the third rail network.7
The majority was originally electrified at 6,250 V, converted to 25 kV in the early 1960s.
- Converted from 1,500 V DC (see 1,500 V DC section "Shenfield Metro")
- Converted from 6,250 V/1,500 V DC
- Romford to Upminster Line
- Shenfield to Southend Line
- Crouch Valley Line
- Braintree Branch Line
- Colchester to Clacton Line
- Mayflower Line
This covers the lines from London Liverpool Street (Bethnal Green Jn) to Chingford, Enfield Town, Hertford East and Cambridge. In the 1960s the lines to Chingford, Enfield Town and Cheshunt were electrified at 6,250 V, from Cheshunt to Bishop's Stortford and Hertford East at 25 kV. The Lea Valley line between Coppermill Junction and Cheshunt was electrified at 25 kV in 1969. All the 6,250 V areas were converted to 25 kV in 1983. In 1987, electrification was extended from Bishop's Stortford to Cambridge at 25 kV. In 1990 the line to Stansted Airport opened, and in 1992 electrification was extended from Cambridge to King's Lynn along the Fen Line.
- Electrified in two parts: 1975-78, and 1984-91
- The line between London (Kings Cross) and Royston was electrified between 1976 and 1978 as part of the Great Northern Suburban Electrification Project. This included the Hertford Loop Line.
- In 1984, authority was given to electrify to Edinburgh and Leeds. The section between Hitchin and Peterborough was completed in 1987, and Doncaster and York were reached in 1989. By 1990 electrification had reached Newcastle, and in 1991 Edinburgh.
- In order to keep construction teams working, two additional schemes were authorised, to Carstairs and North Berwick (North Berwick Line).
- At the peak of the electrification project during the late 1980s, it was claimed to be the "longest construction site in the world" at over 250 miles (400 km).
- Electrified between London (St Pancras) and Bedford in 1983, and Dock Junction to Moorgate - now cut back to Farringdon.
- Electrification from Bedford to Sheffield via Derby, Trent Junction to Nottingham and Kettering to Corby are expected by 2018 as part of the Department for Transport High Level Output Specification for 2014-2019.
- Electrified from the late 1950s to the mid-1960s under the BR 1955 Modernisation Plan to Crewe (and branches), extended to Glasgow in 1974.
- Northampton: see Northampton Loop Line.
- Birmingham (New Street): see Rugby-Birmingham-Stafford Line.
- Liverpool (Lime Street)
- Manchester (Piccadilly): see Stafford to Manchester Line and Crewe to Manchester Line.
- Glasgow (Central): in 1974, from Weaver Junction
- The "Abbey Flyer" (St Albans Branch Line) was electrified 1987-88 by Network SouthEast.
- Edinburgh (Waverley) in 1989 (from Carstairs Junction in conjunction with ECML electrification)
- In 2003, the Crewe to Kidsgrove section of the Crewe to Derby Line was electrified as a diversionary route for the WCML.
- Since 1999 the line has been modernised and the overhead line equipment has been refurbished and renewed as part of a plan to increase train speeds from 110 mph to 125 mph.
- In 1991 the ECML to Edinburgh was electrified. A few local routes were electrified, but most local services were not.
- Edinburgh Crossrail: Edinburgh Waverley to Newcraighall. The service is by DMUs, pending reopening of part of the Waverley Line.
- North Berwick Line: Edinburgh Waverley to North Berwick
- Glasgow to Edinburgh via Carstairs Line: some North Berwick Line trains continue to Glasgow Central. Intercity trains from the ECML continue to Glasgow Central.
- Central Scotland
The route from Edinburgh to Glasgow via Bathgate has been reinstated between Bathgate and Airdrie and electrified throughout. It opened on 11 December 2010. Approval has also been given by the Scottish Parliament for electrification of the main inter-city route between Edinburgh and Glasgow Queen Street High Level via Falkirk. The project, known as EGIP, was scheduled to encompass infill electrification in the Glasgow area and Greenhill Junction to Stirling, Dunblane and (recently re-opened) Alloa, which mainly carry commuter services, but these were removed in 2012 as part of a cost review.
- Glasgow Suburban
Suburban electrification was begun during the 1960s in the wake of the BR 1955 Modernisation Plan. Electrification was piecemeal during the preceding year and is still incomplete, with several suburban, rural and intercity lines still unelectrified.
The Glasgow Suburban railway network can be divided into three main areas:
- North Clyde: also known as the "Glasgow North Electric Suburban Line", one of the first lines in Glasgow electrified in 1960 (Helensburgh Central, Balloch and Milngavie to Glasgow Queen Street (Low Level) and to Springburn and Airdrie).
- South Clyde: the Cathcart Circle Line (Glasgow Central to Newton and Neilston) was electrified on 22 May 1962.8 The Inverclyde Line (Glasgow Central to Gourock and Wemyss Bay) was electrified in 1967.8 The Ayrshire Coast Line (Glasgow Central to Ayr, Largs and Ardrossan Harbour) was electrified in 1986–1987.9 The Paisley Canal Line was electrified to Corkerhill from Glasgow Central, in late 2012 extended to Paisley.
- Argyle Line: between Dalmuir and Milngavie via Glasgow Central (Low Level) to Hamilton Circle, Larkhall, Lanark and Carstairs (via Hamilton, Motherwell or Holytown). There is also peak service to Coatbridge Central.
On the Glasgow to Edinburgh via Carstairs Line, some North Berwick Line trains continue to Glasgow Central. A single daily East Coast intercity train from the ECML continues to and from Glasgow Central. On the Motherwell to Cumbernauld Line, Motherwell to Coatbridge is electrified: Coatbridge to Cumbernauld will be under the EGIP project. On the Shotts Line Holytown Junction to Kirknewton is not electrified, but both ends are, shared with the WCML, Argyle Line and ECML. The Whifflet Line between Whifflet and Rutherglen via Carmyle is not electrified, although there are plans to do so by 2014.10 Whifflet station is electrified, as part of the Motherwell to Cumbernauld line.
- Leeds area
In 1994, a project to electrify some of the local lines around Leeds was given authority to proceed. The project was called the "Leeds North West Electrification", which electrified:
- Airedale line to Skipton and Bradford Forster Square
- Wharfedale line to Ilkley
- Wakefield line electrified in 1989 as part of the East Coast Mainline electrification to London King's Cross
- Harrogate line: proposed; business case submitted
- Manchester area
- Manchester to Glossop / Hadfield (converted from the truncated 1500 V DC Manchester-Sheffield-Wath electric railway)
- Manchester, South Junction and Altrincham Railway (part was converted to Manchester Metrolink)
- Styal Line (primarily operated by diesel multiple units)
- Stafford to Manchester Line: branch of the WCML, electrified in the wake of the BR 1955 Modernisation Plan
- Crewe to Manchester Line: branch of the WCML, electrified in the wake of the 1955 Modernisation Plan
- Northern Hub
- Liverpool to Manchester Line: Manchester to Newton-le-Willows completed December 2013; to Liverpool by December 2014.1112
- Liverpool to Wigan Line, by December 2014.13
- Manchester to Preston Line (via Bolton): by December 2016.1411
- Preston to Blackpool North: by May 20161415 - an extension of the Manchester to Preston Line, this will provide an electrified route from Blackpool to Manchester and the West Coast Main Line
- Huddersfield Line (also known as Manchester to Leeds and York via Stalybridge): expected between 2016 and 2018.1416
- West Midlands
- West Coast Main Line routes electrified in the 1960s:
- Commuter lines out of Birmingham New Street:
Electrified in 1994 between London Paddington and Heathrow Airport in a joint venture between British Rail and the British Airports Authority. As part of Crossrail, the electrified section will be extended to Maidenhead. Maidenhead to Bristol and Cardiff, Newbury and Oxford are to be electrified as part of the GWML upgrade.17
- Tyne and Wear Metro: The Tyne and Wear Metro, which opened in 1980, is now the only system left in the UK using the 1500 V DC overhead lines. Although it is often described as "light rail" it is closer to a heavy metro, using only segregated track. Much of its route follows that of the previous Tyneside Electrics, which had been converted to diesel by 1967. Since 2002, the Metro has shared main-line track on the Durham Coast Line to Sunderland. This presents a potential problem for main-ine services if routes into Sunderland or Newcastle upon Tyne that use this section be electrified at 25 kV AC.
- Blackpool Tramway: originally 550 V, in 2011 upgraded to 600 V to operate more modern rolling stock.
- Southern Electric
The London and South Western Railway (L&SWR) third-rail system at 660 V DC began before World War I from Waterloo to suburban destinations. The Southern Railway was formed in the 1923 grouping; it adopted the L&SWR system, and by 1929 the London, Brighton and South Coast Railway (LB&SCR) suburban overhead network was replaced by third rail. The South Eastern Main Line was electrified at 600 V, later upgraded to 750 V DC. The third rail extended throughout most South London lines out of all its London termini. Throughout the 1930s there was much main line electrification, including the Brighton mainline (including East, West Coastways and related routes in 1932-1933), the Portsmouth Direct Line (4 July 1937) and to Maidstone and Gillingham (1939).
After World War II, electrification was soon resumed in the newly nationalised British Rail's Southern Region. The BR 1955 Modernisation Plan included the two-stage "Kent Coast Electrification". The Chatham mainline was completed, followed by the SER mainline and related lines. The voltage was raised from 660 V to 750 V.18 Since then, all electrification has used 750 V; lines electrified before then remain at 660 V. Attention then switched to the neglected former L&SWR area (then the South Western Division). The South Western Main Line (SWML) to Southampton and Bournemouth was electrified in 1967 and to Weymouth in 1988. The Island Line was electrified in 1967.
During sectorisation in the 1980s, Network SouthEast conducted extensive infill electrification. The Snow Hill tunnel was reopened, enabling Thameslink. The Hastings Line, Eastleigh to Fareham Line and the Oxted Line (East Grinstead branch) were electrified. This left only a few lines unelectrified: the West of England Main Line, the North Downs Line, the Oxted Line (Uckfield branch), and the Marshlink Line.
This uses 750 V1920 (see Suburban electrification of the London, Midland and Scottish Railway for its history).
- Euston and Broad Street to Watford Junction and Croxley Green (Watford DC Line)
- Richmond – North Woolwich (North London Line)
See Suburban electrification of the London, Midland and Scottish Railway for its history.21 In 1970 the North London DC lines and the Class 501 EMUs used on these services were converted for third-rail operation, with the fourth rail generally being removed on sections not used by LUL. Some fourth rail was retained in the Gunnersbury and Queens Park areas for emergency use by LUL. With the closure of Broad Street, the North London Line was joined with the Stratford to North Woolwich line; this was electrified with third rail and overhead line as far as Stratford, third rail to North Woolwich. Two branches of the Watford DC Line have been closed: to Rickmansworth in 1952 (to passengers, to goods in 1967) and to Croxley Green in 1996.
The Watford DC Line between Queens Park and Harrow & Wealdstone and the North London Line between Richmond and Gunnersbury are used by London Overground trains designed for 750 V third rail and Bakerloo Line trains designed for 630 V third and fourth rail. As a compromise the nominal line voltage is 650 V, and the centre rail is bonded to the return running rail. There are no special provisions required at Queens Park, where the two dissimilar systems meet, just a gap longer than one coach of a Bakerloo Line train at the entry to (and exit from) the Bakerloo, which operates with a nominal -210 V on the fourth rail and +420 V on the third rail. There is no bridging of the incompatible systems as trains pass from one to the other since, like all UK electric trains intended to run extensively in tunnels, there is no continuity of traction power circuits between vehicles of the train.
The Northern City Line connects the East Coast Main Line to Moorgate. It was isolated by the abandonment of the 1930s "New Works" programme (and the development of the Metropolitan Green Belt). Tube services were truncated at its northern end by the Victoria Line in 1964 at Drayton Park. The remainder was handed over to BR in 1975 in conjunction with the suburban electrification of the East Coast Main Line. The line uses 25 kV AC overhead and third-rail DC electrification at 750 volts, with the switchover at the platform at Drayton Park.
The London Underground is a large metro system operating across London and beyond, commonly known as "the Tube". It 408-kilometre (254 mi)22 is made up of 11 lines; electrification began during the 1890s. It was largely unified between 1900 and 1910 and nationalised in 1933, becoming the railway component of London Transport (LT). A major expansion programme (the "New Works") was launched, in which LT took over several urban branches of mainline railways.
The Underground is mostly in north London; its expansion into south London was limited by geology unfavourable to tunnelling and by the extensive main-line network, much of which was being electrified (see "Southern Electric"). The Underground uses a relatively uncommon four rail system of electrification. Two standard gauge rails are the running rails; the outer third rail carries positive current at +420 V DC and the inner fourth rail is the negative return at –210 V DC, giving a supply voltage of 630 V DC. The chief advantage of the fourth-rail system is that, in tunnels with a metallic (usually cast-iron) lining, the return traction current does not leak into the lining causing electrolytic corrosion there or in the neighbouring utility mains. The two running rails are available exclusively for track circuits.
The surface sections use the fourth rail solely for operational consistency; the system shares track with Network Rail in several places. Some of these are non-electrified sections of the national railway network (e.g. Chiltern Railways out of Marylebone station), and diesel trains are used. The suburban network of the London & North Western Railway (LNWR) was electrified in co-operation with the Underground, but during the 1970s British Rail introduced third-rail EMUs and the sections of the LNWR suburban network not used by the Underground had the fourth rail removed (see "London and North Western Railway", above).
This uses bottom-contact composite third rail, with an aluminium body and a steel contact surface. The advantage of this is a low-resistance, high-current-capacity rail with a durable steel surface for current collection. The rail may be surrounded by insulating material on the top and sides to reduce the risk of electrocution to railway staff and trespassers. The bottom-contact system is less prone to derangement by snow than top contact.
- Glasgow Subway, electrified in 1935
- Hythe Pier Railway, electrified in 1922
- Volk's Electric Railway was originally electrified at 50 V DC, raised to 160 V in 1884 and reduced to 110 V DC during the 1980s.
- The elevated "monorail" at the National Motor Museum, Beaulieu uses rubber tyres running on two metal tracks, one on either side of the central guide. Because it is rubber-tyred, it requires two current conductors and two collectors (hence the four-rail designation).
Great Britain has used different electrification systems in the past. Many of these date from the early part of the 20th century, when traction electricity was in the experimental stage. This section describes each system, in order of decreasing voltage.
- Lancaster to Heysham via Morecambe: Used for an early trial of electrification; operated between 13 April and 14 September 1908.
- 'Elevated Electric' London suburban lines of the London, Brighton and South Coast Railway: The first large-scale suburban electrification scheme; starting with the Inner South London Line and then extended to other commuter lines around the south of London, operational from 1 December 1909. Following the grouping into the LBSCR into the Southern Railway in 1922, all of the 6,600 V lines were converted to the 650V DC third rail system by September 1929.
During the initial electrification of parts of the network to 25 kV 50 Hz AC overhead, the initial solution to the limited clearance problems in suburban areas (due to numerous tunnels and bridges) in London and Glasgow was to use the lower voltage of 6,250 V. Later technological improvements in insulation allowed these areas to be converted to 25 kV. The last sections of 6,250 V were converted during the 1980s.
- London, Tilbury and Southend Lines
The 6.25 kV section was from Fenchurch Street to beyond Barking, with changeovers there on both the Upminster and Tilbury lines. The section between Chalkwell and Shoeburyness was also at 6.25 kV.23 The remainder was at 25 kV. The sections electrified at 6,250 V were converted to 25 kV during the early 1980s.
- Great Eastern Lines
The line from Liverpool Street to Southend Victoria was originally electrified at 1,500 V DC overhead during the 1940s-50s. During the early 1960s, the whole of this line was converted to 6,250 V AC overhead, while the main line east of Shenfield was progressively electrified at 25 kV, with changeover east of Shenfield. During the early 1980s the line was again converted, this time to 25 kV.
The Cambridge line and branches from Liverpool Street was electrified in the early 1960s, with 6.25 kV out to a changeover at Cheshunt, and 25 kV beyond. The Chingford and Enfield lines were thus at 6.25 kV throughout. This route was again fully converted to 25 kV in the early 1980s.
As part of the electrification onwards to Cambridge and Norwich in the 1980s, electric locomotives were transferred to these routes from the West Coast route. These locomotives would not have been able to operate at 6.25 kV.
- Glasgow Suburban network
On the North Clyde the central section between Parkhead and before Dalmuir (Clydebank loop) and Westerton (Anniesland loop) were at 6.25 kV, with the outer sections at 25 kV. The Bridgeton and Springburn branches were thus at 6.25 kV throughout. The sections electrified at 6,250 V were converted to 25 kV during the early 1980s.
On the South Clyde the route from Glasgow Central around the Cathcart Loop was initially at 6.25 kV, with changeovers to 25 kV at Kings Park and Muirend on the Motherwell and Neilston routes. These lines were progressively converted to 25 kV in the 1970s-80s.
- Bury to Holcombe Brook
After World War I, the UK Government set up a committee to investigate the various systems of railway electrification; in 1921, it recommended that 1,500 V DC overhead should be the future national standard.1 Several schemes were implemented in its wake, but the Great Depression and World War II meant very little work was done. Technological advances after 1945 meant the 25 kV AC system was adopted instead for the West Coast Main line and Glasgow suburban electrification (as set out in the BR 1955 Modernisation Plan). However, at the same time large amounts of money had been (and were still being) spent converting several lines to 1,500 V DC.
A joint LMS and LNER scheme, it opened on 11 May 1931. The success of this scheme influenced LNER's later electrification schemes. The line was converted to 25 kV AC in 1971, but the stretch between Altrincham and Trafford Bar (plus the stretch between Trafford Bar and the Cornbrook viaduct) were later incorporated into Manchester Metrolink and converted again (this time to 750 V DC).25
Known as the Woodhead Route, the LNER chose this hilly (and busy) mainline for its first mainline electrification, with work beginning in 1936.26 Due to the Depression and World War II, it was not completed until the 1950s. After completion, the government chose to standardise on 25 kV AC instead, leaving the Woodhead Route and the few other 1,500 V DC lines isolated and non-standard. The passenger locomotives were sold in 1969 and saw further service in the Netherlands. In a subsequent rationalisation, BR closed much of this route east of Hadfield in 1981 in favour of the more southerly Hope Valley Line, which serves more local communities. A section of the line between Manchester, Glossop and Hadfield remained open as part of the Manchester suburban network, and was operated by Class 506 EMU's, until it was converted to 25 kV AC in December 1984.
- Shenfield Metro
The LNER decided to electrify the Liverpool Street to Shenfield section of the Great Eastern Main Line (GEML), known as the Shenfield Metro. Civil engineering works began during the 1930s, but World War II intervened. Work was completed in 1949 and extended to Chelmsford and Southend Victoria in 1956, using Class 306 (AM6) EMUs.27 It was converted to the new standard of 25 kV AC (initially with some sections at 6,250 V) on 4–6 November 1960, in the wake of the BR 1955 Modernisation Plan which called for 25 kV AC to be the new standard. The rest of the GEML was subsequently electrified.
- Shildon to Newport
This line ran from Shildon (County Durham) to Newport (near Middlesbrough). The route was initially over the 1825 Stockton-to-Darlington line, then via Simpasture Junction (the former Clarence railway) through Carlton, Carlton Junction to Carlton South Junction, Bowesfield West Junction to Bowesfield Junction, through Thornaby and ending at Erimus Yard (Newport East). In the wake of the electrification of Tyneside by the NER, this coal-carrying line was electrified between 1 July 1915 and 1 January 1916 as a planned precursor to electrifying NER's busy York to Newcastle main line (part of the ECML). The LNER removed this electrification system in 1935 (between 7 January and 8 July); the decline in the coal market made it economically unfeasible to undertake the significant renewals required to continue electric operation. The locomotives were stored for other electrified routes.282930
- Manchester Victoria - Bury
In 1917, the line between Manchester Victoria and Bury was electrified using 1,200 V DC third rail (side contact). The line between Bury and Holcombe Brook which had been electrified using 3,500 V DC overhead in 1913 was converted to this system in 1918. It was abandoned in 1991, when the line was converted to a 750 V DC system and became part of the Manchester Metrolink.3132
This was electrified in 1904, in response to extensive competition from new electric trams. The concept was a success for the North Eastern Railway (NER), a noted pioneer in electrification, as passenger numbers returned to pre-tram levels.33 As the stock reached life expectancy in 1937, the network was remodelled by London and North Eastern Railway (LNER) to reflect the changing industrial and residential makeup of the area.34 Electrified at the same time was the dockside branch, where a pair of Class ES1 (formerly NER No.1 and 2) locomotives were introduced in 1905. These British Thomson-Houston locomotives operated from both the third rail and overhead line. British Rail brought in third-rail stock (12 2EPBs) from the Southern Region in 1955. British Rail removed the electrification between 1963 and 1967, citing the changing industrial and population makeup of the area which reduced the need for electric traction. Much of the Tyneside network was later re-electrified (using 1500 V DC overhead) as the Tyne and Wear Metro.
The Liverpool Overhead Railway was one of the earliest electric railways in Great Britain. The first section, between Alexandra Dock and Herculaneum Dock, was opened in 1893. The line connected with Lancashire and Yorkshire Railway's North Mersey Branch. It was never nationalised, and closed on 30 December 1956 due to extensive corrosion throughout its iron infrastructure (which was deemed uneconomical to replace).
The City and South London Railway electrification was unusual (compared with later schemes) in that it used a three-wire DC system. This meant that although the offset centre third rail was electrified at +500 volts in the northbound tunnel, it was electrified at -500 volts in the southbound tunnel. The motors on the locomotives and the incandescent electric lamps in the carriages worked, regardless of the polarity of the supply. The three-wire system was adopted because the initial system was fed directly from the dynamos in the surface power plant at the Stockwell end of the line. It was important to minimise the voltage drop as much as possible, bearing in mind the rather steep gradient on the approach to King William Street station.
In 2006, 3,062 miles (4,928 km) of the British rail network was electrified, and 60 percent of all rail journeys were by electric traction (both by locomotives and multiple units).35 According to Network Rail, 66 percent of the electrified network uses the 25 kV AC overhead system, and 36 percent uses the 660/750 V DC third-rail system.35
- Suburban electrification of the London, Midland and Scottish Railway
- Manchester-Sheffield-Wath electric railway
- Volk's Electric Railway
- Electrification of Railways Advisory Committee Final Report. London: HMSO. 1921
- Modernisation of British Railways: The System of Electrification for British Railways. London: British Transport Commission. 1956
- Delivering a Sustainable Railway - White Paper CM 7176dead link
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- "Modernising the Great Western". Network Rail. p. 8. Retrieved 11 November 2011.
- Rail Magazine: Issue 673, Page 14-15, 29 June - 12 July 2011.
- http://assets.dft.gov.uk/publications/hlos-2012/railways-act-2005.pdf paragraph 37
- Little, Stuart M. (December 1979). "Greater Glasgow's Railway Network". Scottish Transport. No. 33: 2–12. ISSN 0048-9808.
- Garry Keenor (2010-11-13). "The Rebirth of AyrLine: Electrification to Ayr / Ardrossan / Largs - 1986/1987". Railwaysarchive.co.uk. Retrieved 2010-11-17.
- North West Electrification, Network Rail. Accessed 16 July 2012
- "Rail Electrification - July 2009". p. 22.
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- Eric Peissel & Robert Schwandl. "> Europe > UK > England > LIVERPOOL MERSEYRAIL". UrbanRail.Net. Retrieved 2010-11-17.
- "London And North Western Railway Electrification to Watford and Richmond". Easyweb.easynet.co.uk. Retrieved 2010-11-17.
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- British Rail Locomotives and other motive power: Combined volume. London: Ian Allan. 1968. p. 11. ISBN 0-7110-0008-5.
- Lancashire and Yorkshire Railway Societydead link
- "The Manchester South Junction & Altrincham (BR Class 505) Stock". The London & North Eastern Railway (LNER) Encyclopedia. 2007. Retrieved 2007-01-17.
- "Woodhead Railway and its Electrification". Wortley Top Forge Industrial Museum. 2007. Retrieved 2007-04-14.
- "The Liverpool Street to Shenfield Route AM6 (Class 306) Stock". The London & North Eastern Railway (LNER) Encyclopedia. 2007. Retrieved 2007-01-17.
- Williams, Stephen (Nov–Dec 1985). "The Newport - Shildon Electrification of the North-Eastern Railway". Electric Railway Society Journal (Electric Railway Society) 30 (180).
- "NER locomotive 3 to 12". Desertrailways.tripod.com. Retrieved 2010-11-17.
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- "The LNER Tyneside Electric Multiple Units". The London & North Eastern Railway (LNER) Encyclopedia. 2007. Retrieved 2007-01-17.
- Network Rail, 2003 Technical Plan, Chapter 11 "Network Capability", page 7 "Electrification". "Approximately 40% of the rail network is currently equipped with electrification. From page 1, total network is 30,764 km, 7,587 km of 25 kV AC, 4,285 km of 650/750 V DC and 28 km of 1500 V DV. Excludes CTRL, LUL, Old Danby test track, bulk of Tyne and Wear Metro, etc. NB it does not state what method of counting length of network is used - i.e. sidings, loops, double track etc. produce different numbers. The UIC statistics that are used in the chart showing electrification in Europe is based solely on line length. Thus on this count, 11,900 km (38.7%) is electrified. Of the electrified network, 65.8% is 25 kV AC, 36.0% is 650/750 V DC and 0.2% is 1,500 V DC.
- Box, Charles E. (1959). Liverpool Overhead Railway. Railway World Ltd.
- Gahan, John W. (1992). Seventeen stations to Dingle - The Liverpool Overhead Railway remembered. Countyvise and Avon-Anglia. ISBN 0-907768-20-2.
- Bolger, Paul (1992). The Docker's Umbrella - A History of Liverpool Overhead Railway. The Bluecoat Press. ISBN 1-872568-05-X.
- Jarvis, Adrian (1996). Portrait of the Liverpool Overhead Railway. Ian Allan. ISBN 0-7110-2468-5.
- Maund, T.B. (2001). Merseyrail Electrics - The Inside Story. NBC Books. ISBN [[Special:BookSources/0-9531896-1-3|0-9531896-1-3 [[Category:Articles with invalid ISBNs]]]] Check
- Moody, G.T. (1979). Southern Electric 1909-1979. Ian Allan. ISBN 0-7110-0924-4.
- Glover, John (2001). Southern Electric. Ian Allan. ISBN 0-7110-2807-9.
- Appleby, K.C. (1990). Shildon - Newport in Retrospect. Lincoln: Railway Correspondence and Travel Society. ISBN 0-901115-67-3.
- Dixon, Frank (1994). The Manchester South Junction & Altrincham Railway. The Oakwood Press. ISBN 0-85361-454-7.
- Goslin, Geoff (2002). London's Elevated Electric Railway - The LBSCR Suburban Overhead Electrification 1909-1929. Connor & Butler Ltd. ISBN 978-0-947699-35-2.
- Nock, O.S. (1966). Britain's New Railway. Ian Allan.
- Nock, O.S. (1974). Electric Euston to Glasgow. Ian Allan. ISBN 0-7110-0530-3.
- Boocock, Colin (1991). East Coast Electrification. Ian Allan. ISBN 0-7110-1979-7.
- Semmens, Peter (1991). Electrifying the East Coast Route. Patrick Stephens Ltd. ISBN 0-85059-929-6.
- Glover, John (2003). Eastern Electric. Ian Allan. ISBN 0-7110-2934-2.
- Citytransport.info's Electrification advocacy page
- Kent Rail
- Lancashire & Yorkshire Railway Society Archived 12 July 2006 at the Wayback Machine
- Southern E-mail Group
- Southern Electric Group
- Suburban Electric Railway Association