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40% (3,062 miles / 4,928 km) of the British rail network is electrified and 60% of all rail journeys are by electric traction (both by locomotives and Multiple Units).

Railway electrification as a means of traction emerged at the end of the nineteenth century. It offered several benefits over the then predominate steam traction, particularly in respect of its quick acceleration (ideal for urban (metro) and suburban (commuter) services) and power (ideal for heavy freight trains through mountainous/hilly sections). A plethora of systems emerged in the first twenty years of the twentieth century (as listed below). In 1928 a government committee agreed 1500V DC overhead as the national standard, although little work was done to implement this and the plethora of different systems continued to exist (and even expand).

After World War II, with nationalisation (1948), British Rail expanded electrification (1500V DC and the Southern third rail) but soon (mid 1950s) adopted 25kV AC overhead for its proposed mainline electrification.

Despite the following years of minimal capital investment, the 25kV AC network has continued to expand, slowly, although large areas of the country are still non-electrified, despite their urban, suburban, hilly or intercity nature.

Contents 1 Rail-based (Third and Fourth rails) 1.1 650V to 850V DC Third rail 1.2 630V DC Fourth Rail 1.3 1200V DC Side-Contact rail 2 Overhead 2.1 1500V DC Overhead 2.2 3500V DC Overhead 2.3 6600V (6.6kV) AC Overhead at 25 Hz 2.4 6250V (6.25kV) AC Overhead at 50 Hz 2.5 25000V (25kV) AC Overhead at 50Hz 3 See also 4 References 5 External links

[edit] Rail-based (Third and Fourth rails)

[edit] 650V to 850V DC Third rail

• L&SWR / Southern Railway / Southern Region of British Railways - everything but a few freight branches, Marshlink, North Downs Line, Uckfield branch of the Oxted Line and services through Salisbury.
• Northern City Line - East Coast Main Line to Moorgate - A former main line taken over by the Underground and turned into a tube line. It was however isolated by the abandonment of the 1930s "New Works" programme (and the development of the greenbelt). Tube services were further truncated by the new Victoria Line in 1964 (which shortened the northern end of the line). The remainder was handed over to BR in 1975 in conjunction with electrification of East Coast Main Line to allow dual voltage (ie both 25kV AC Overhead and Third Rail DC) commuter trains into London. A link with the East Coast Main Line was made to enable this. Presumably third rail was chosen as the tunnels were of too narrow a bore to allow overhead lines to be installed (as they are on the Snowhill, Thameslink route.)
• Merseyrail Electrics (Merseyrail) - A history can be found here. See also[1]
• Liverpool Overhead Railway - Earliest electric railway in the UK (1893), it connected with Lancashire and Yorkshire Railway's North Mersey Branch. It was never nationalised and it closed on the 30th December 1956 due to extensive corrosion throughout its iron infrastructure (which was deemed uneconomical to replace).
• Glasgow Subway - 600V dc, in 1935.
• Tyneside Electrics - 630V DC(de-electrified by BR in 1960 then turned into Tyne and Wear Metro )

• Docklands Light Railway (bottom-contact third rail)

[edit] 630V DC Fourth Rail

• London Underground
• LNWR - London suburban network - Euston and Broad Street to Watford Junction, Croxley Green and Richmond ( North London Line and Watford DC Line ). A short history can be found here.

Refrence[2]

The Watford DC Line between Queens Park and Harrow & Wealdstone is peculiar in that it is used by both Silverlink Metro trains, designed for 750V third rail, and Bakerloo Line trains designed for 630V third and fourth rail. Consequently the voltage is set at a suitable compromise value around 690V nominal, and the centre rail is at the same potential as the return running rail, whereas in normal London Underground usage the traction supply floats with the centre rail at nominally -230V and the outer rail at nominally +420V. giving 630V overall.

[edit] 1200V DC Side-Contact rail

• Manchester Victoria - Bury This very busy commuter line was electrified by the Lancashire and Yorkshire Railway in 1913 to 3500V DC overhead (see above). In 1917 the L&YR converted it to side-contact third rail. This system was abandoned when the line was converted to become part of the Manchester Metrolink. [3] and [4]

[edit] Overhead

[edit] 1500V DC Overhead

In the wake of World War One, the British Government set up a committee to investigate the various systems of railway electrification and in 1928 it reported that 1500V DC overhead should be the future national standard. Several schemes (see below) were implemented in its wake, although the Great Depression and World War Two meant very little work was done. Technological advances post war saw a government U turn and the 25kV AC system was adopted instead for the West Coast Main line and Glasgow suburban electrification as set out in the 1955 BR modernisation plan - at the same time the large amounts of money had/were still being spent converting several lines to 1500V DC.

• Manchester, South Junction and Altrincham Railway - A joint LMS and LNER effort, opened on the 11th May 1931, it was a test bed for both companies for the new standard (which at the time had not been implemented in the UK) in this largely self-contained busy suburban line. The success of this scheme propelled LNER's latter electrification efforts. The line was latter converted to 25kV AC in 1971 but then parts converted to the Manchester Metrolink (a tram system).

• Manchester-Sheffield-Wath line. Known as the Woodhead Route. LNER, chose this hilly and busy mainline for its first mainline electrification, with work starting in 1936 [5]. Due to the depression and World War Two it wasn't completed until the 1950s. However upon completion the government chose to utilise 25kV AC instead, leaving the few 1500V DC lines isolated and non-standard. Subsequent BR rationalisation (the Beeching Axe) saw large parts of this route closed east of Hadfield in 1981 (in favour of a route with more local communities). The remaining stub in Manchester was converted to 25kV AC in December 1984.

• Shenfield Metro (Great Eastern Main Line) - Electrified post war (early 1950s), although LNER had been planning this since the early 1930s. It was soon converted to 25kV AC, initially with some sections at 6.25kV, in the wake of the 1955 BR Modernisation plan.

• Newport (near Sunderland) to Shildon (County Durham) line. In the wake of the electrification of Tyneside by the NER, this coal carrying line was electrified, as a precursor to electrifying NER's busy York to Newcastle mainline (Part of the ECML). It was dismantled by LNER around 1934/1935. [6], [7], [8], [9], [10]

• Tyne and Wear Metro Despite the abandonment in favour of 25kV AC overhead in the 1950s, large parts of the former "Tyneside Electrics" routes (which had been electrified using third rail until the 1960s when BR discontinued the "non-standard" equipment in favour of diesels) were rebuilt as the "Tyne and Wear Metro" in the 1970s. Styled as "Light Rail" it is in practice normal heavy rail, and even shares some lines with the current rail network (unlike the other tram systems in the UK which operate alongside but on separate rights of way).

[edit] 3500V DC Overhead

• Bury to Holcombe Brook This was electrified by the Lancashire and Yorkshire Railway in 1913 as part of a trial system for export. The system was converted to third rail in 1917 (see above). [11]

[edit] 6600V (6.6kV) AC Overhead at 25 Hz

• LBSCR's London urban/metro lines
• Lancaster to Heysham via Morecambe (Morecambe Branch Line)

[edit] 6250V (6.25kV) AC Overhead at 50 Hz

During the initial electrification of parts of the network to 25kV AC overhead the initial solution to the limited clearance problems in suburban areas (due to numerous tunnels and bridges) – notably London and Glasgow – was to use the lower voltage of 6.25kV AC Overhead. Latter technological improvements in insulation allowed these area to be converted to 25kV AC Overhead.

• Shenfield Metro (Great Eastern Main Line) - electrified in the 1950s (1500V DC overhead) and 1960s (converted to 25kV)
• Parts of Glasgow Suburban network (see SPT and Transport in Glasgow) electrified in the 1960s
  • North Clyde Line - the central area, Springburn, Bridgeton and Milngavie branches and the Yoker loop)
  • Cathcart Circle Line

[edit] 25000V (25kV) AC Overhead at 50Hz

• London, Tilbury and Southend (LTS) - converted from 6.25kV AC overhead

• Great Eastern Main Line (GEML) - converted from 6.25kV AC overhead and 1500V DC overhead
  • Romford to Upminster Line
  • Shenfield to Southend Line
  • Crouch Valley Line
  • Braintree Branch Line
  • Colchester to Clacton Line
  • Mayflower Line

• East Coast Main Line (ECML) - in the 1980s, including two branches;
  • Hertford Loop Line
  • North Berwick Line

• Midland Main Line (MML) (south of Bedford) - in the 1980s, see also Thameslink

• West Coast Main Line (WCML) - in the 1950s under the 1955 BR modernisation plan as far as Crewe (and branches), it was extended to Scotland in the 1970s.
  • 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 associated "Abbey Flyer" (St Albans Branch Line) was electrifed 1987-88 by Network SouthEast
  • Edinburgh (Waverley) in 1989 (from Carstairs Junction in conjunction with ECML electrification).
  • In 2003 Crewe to Kidsgrove section of the Crewe to Derby Line was electrified as a diversionary route for the WCML.

• Edinburgh - see also Transport in Edinburgh. 1989 saw the electrification of the ECML which goes through Edinburgh, at the time a few local routes were electrified, but the majority of local services are unelectrified.
  • Edinburgh Crossrail - Only Edinburgh Waverley to Newcraighall, currently the service is by DMUs, pending reopening of part of the Waverley Line
  • North Berwick Line - Edinburgh Waverley to North Berwick, with some extensions to Edinburgh Haymarket.
  • Glasgow to Edinburgh via Carstairs Line - Some North Berwick Line trains continue to Glasgow Central. GNER intercity trains (from the ECML) continue to Glasgow Central.

• Glasgow Suburban (see SPT and Transport in Glasgow) - Suburban electrification was started in the 1960s in the wake of the 1955 BR modernisation plan. Electrification was piecemeal over the preceding year and is still incomplete with several suburban, rural and inter city lines still unelectrified. Rail expansion plans call for reopening of the Airdrie-Bathgate Rail Link, connecting the North Clyde Line and Edinburgh to Bathgate Line.
  • Argyle Line - Dalmuir and Milngavie via Glasgow Central (Low Level) to Hamilton Circle, Larkhall, Lanark and Carstairs (via a variety of lines via Hamilton, Motherwell or Holytown). There is also a peak time branch to Coatbridge Central
  • Ayrshire Coast Line - Glasgow Central to Ayr, Largs and Ardrossan Harbour, electrified in 1986/87. See The Rebirth of AyrLine: Electrification to Ayr / Ardrossan / Largs - 1986/1987
  • Cathcart Circle Line - ( Glasgow Central to Newton and Neilston) was electrified on 22nd May 1962 <ref name = Little> Little, Stuart M. (December 1979). "Greater Glasgow's Railway Network". Scottish Transport No. 33: 2 - 12. ISSN 0048-9808.</ref>
  • Glasgow to Edinburgh via Carstairs Line - Some North Berwick Line trains continue to Glasgow Central. GNER intercity trains (from the ECML) continue to Glasgow Central.
  • Inverclyde Line - (Glasgow Central to Gourock and Wemyss Bay), this was electrified in 1967 <ref name=Little/>.
  • Motherwell to Cumbernauld Line - The Motherwell to Coatbridge section is electrified, but the Coatbridge to Cumbernauld section of the line is not.
  • North Clyde Line - Also known as "Glasgow North Electric Suburban Line", This was one of the first lines in Glasgow to be electrified in 1960. Helensburgh Central, Balloch and Milngavie to Glasgow Queen Street (Low Level) and out to Springburn and Drumgelloch.
  • Paisley Canal Line - Electrified only as far as Corkerhill (from Glasgow Central)
  • Shotts Line - The central section (Holytown Junction to Kirknewton) is not electrified, however both ends are electrified, as they are shared with the WCML, Argyle Line and ECML.
  • Whifflet Line - The section that follows the WCML (Glasgow Central to Rutherglen) is electrified, the rest of the line to Whifflet is not.

• Leeds area
  • Leeds to Skipton (Airedale Line)
  • Leeds to Bradford
  • Leeds to Ilkley (Wharfedale Line)
  • Leeds branch off the ECML (via Wakefield Westgate) (1980s/early 1990s)

• Manchester area -
  • Manchester to Glossop / Hadfield (converted from the truncated 1,500V DC Manchester-Sheffield-Wath electric railway),
  • Manchester, South Junction and Altrincham Railway (although part of this line was converted to the Manchester Metrolink)
  • Manchester Airport Line (although primarily operated by diesel multiple units)
  • Stafford to Manchester Line - branch of WCML, electrifed in the wake of the 1955 BR Modernisation plan.
  • Crewe to Manchester Line - branch of WCML, electrifed in the wake of the 1955 BR Modernisation plan.

• West Midlands area - A few lines out of New Street mainly related to the West Coast Main Line.
  • Trent Valley Line - WCML, late 1950s.
  • Rugby-Birmingham-Stafford Line - WCML, late 1950s.
  • Birmingham Cross-City Line - Electrified in the early 1990s, re-opening in 1993.
  • Walsall Line - Electrified from New Street to Walsall.

• Great Western Main Line (GWML)
  • Only between Heathrow and London Paddington - see Heathrow Express and Heathrow Connect

• Channel Tunnel Rail Link (CTRL) - employing auto-transformers

• London Crossrail (Proposed)

[edit] See also

• Railway electrification system
• Railroad electrification in the United States
• List of current systems for electric rail traction
• List of railway electrification systems in Japan

[edit] References

[edit] External links

• Citytransport.info's Electrification advocacy page
• Kent Rail
• Soutehrn E Group
• Southern Electric Group
• Suburban Electric Railway Association