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Great Western main line
Maidenhead Railway Bridge carrying the line over the River Thames.
Overview
Type	Commuter rail, Higher-speed rail[1]
System	National Rail
Status	Operational
Locale	Greater London South East England South West England
Termini	London Paddington Bristol Temple Meads
Stations	27
Operation
Opened	30 June 1841 (complete line)
Owner	Network Rail
Operator(s)	Great Western Railway TfL Rail Heathrow Express Chiltern Railways CrossCountry South Western Railway
Depot(s)	North Pole Old Oak Common Reading St Philip's Marsh depot
Rolling stock	InterCity 125 Class 57 Class 150 "Sprinter" Class 153 "Super Sprinter" Class 158 "Express Sprinter" Class 159 "South Western Turbo" Class 165 "Networker Turbo" Class 166 "Networker Turbo Express" Class 220 "Voyager" Class 221 "Super Voyager" Class 332 Class 345 "Aventra" Class 360 "Desiro" Class 387 "Electrostar" Class 800
Technical
Line length	118 mi 19 ch (190.28 km)
Number of tracks	Four (London to Didcot) Two (Didcot to Bristol)
Track gauge	4 ft 8 1⁄2 in (1,435 mm)
Old gauge	7 ft 1⁄4 in (2,140 mm)
Electrification	Mk3b, Series 1 and UK Master Series 25 kV 50 hz AC OLE (Paddington to Didcot Parkway) (Didcot to Thingley Junction by 2019)
Operating speed	125 mph (201 km/h) maximum
Signalling	AWS, TPWS, ATP
Route map (interactive map)

[ v t e ] Great Western Main Line
Legend
miles Circle and Hammersmith & City lines via Liverpool Street Crossrail (under construction) 0⅓ London Paddington Paddington Goods Royal Oak () Mileage Yard Goods & Coal Subway Junction Westbourne Park () Portobello Junction Notting Hill Sidings Circle and Hammersmith & City lines to Hammersmith Kensal Green Gasworks siding Westway (A40) West London Line North Pole depot West London Junction Old Oak Common TMD Old Oak Common Goods Old Oak West Junction Acton–Northolt line Willesden & Acton Brick Co. siding Central line via Liverpool Street North London line Central line Western Avenue (A40) 4¼ Acton Main Line Central line District and Piccadilly lines 5⅝ Ealing Broadway 6½ West Ealing Greenford branch line Plasser works 7¼ Hanwell Wharncliffe Viaduct over River Brent Brentford branch line 9⅓ Southall Grand Union Canal 10⅞ Hayes & Harlington Airport Junction to Heathrow Airport stations 13⅛ West Drayton River Colne Limit of Greater London and TfL area Uxbridge (Vine Street) branch line Staines and West Drayton Railway to Colnbrook Cargo Centre M25 motorway 14¾ Iver Western Rail Approach to Heathrow to Heathrow Central and Terminal 5 (proposed) 16⅛ Langley 18⅜ Slough Slough–Windsor & Eton line 20⅞ Burnham 22⅜ Taplow Jubilee River Maidenhead Railway Bridge over River Thames 24⅛ Maidenhead Marlow branch line 31⅓ Twyford Henley branch line River Loddon Sonning Cutting 1 mile (1.6 km) long 60 feet (18 m) deep River Kennet Waterloo–Reading line North Downs Line Reading East Junction 36⅓ Reading Reading–Basingstoke line and Reading–Taunton line 38⅝ Tilehurst Purley Cutting 41½ Pangbourne Gatehampton Railway Bridge over River Thames 44¾ Goring & Streatley Moulsford Railway Bridge over River Thames Moulsford 48⅜ Cholsey Cholsey and Wallingford Railway (bank holidays and weekends only) Didcot, Newbury and Southampton Railway 53⅛ Didcot Parkway Cherwell Valley line to Oxford, Birmingham and the Cotswold Line Didcot power stations Milton Park estate 56⅜ Steventon Wantage Tramway Wantage Road Challow Uffington Faringdon branch Shrivenham Stratton Park Halt Highworth branch line 77¼ Swindon Golden Valley line to Cheltenham Spa and Birmingham Midland and South Western Junction Railway M4 motorway Wootton Bassett South Wales Main Line Dauntsey Malmesbury branch line Christian Malford Halt Calne branch line 93⅞ Chippenham Thingley Junction Wessex Main Line to Melksham, Bradford-on-Avon and Salisbury Corsham Box Tunnel 2939 yd 2687 m Box (Mill Lane) Halt Box Bathford Halt Bathford Bridge over River Avon Wessex Main Line to Weymouth, Southampton and Brighton Bathampton Junction Bathampton Hampton Row Halt 106⅞ Bath Spa 107⅞ Oldfield Park Somerset and Dorset Joint Railway 108⅞ Twerton-on-Avon Twerton Tunnel Saltford Tunnel Saltford 113¾ Keynsham St Anne's Park No 3 Tunnel 1017 yd 930 m St Anne's Park No 2 Tunnel 154 yd 141 m St Anne's Park River Avon North Somerset Junction Bristol and North Somerset Railway St Philip's Marsh TMD Cross Country Route to Gloucester & Birmingham New Street to Mangotsfield to Ashton Gate Platform 118⅜ Bristol Temple Meads Bristol West Junction Temple Meads Goods Bristol–Exeter line

The Great Western main line is a main line railway in England, that runs westwards from London Paddington to Bristol Temple Meads. Opened in 1841, it was the original route of the pre-1948 Great Western Railway which was merged into the Western Region of British Railways and is now a part of the national rail system managed by Network Rail.

The line is currently being electrified. It was electrified from Paddington to Heathrow Airport in the late 1990s. Work to electrify the remainder of the route started in 2011 with an initial aim to complete the work all the way to Bristol by 2016.^[2] The programme however has been deferred with no end completion forecast because costs have tripled. The four sections deferred are: Didcot Parkway to Oxford, Bristol Parkway to Bristol Temple Meads, Royal Wootton Bassett Junction to Bristol Temple Meads and the Thames Valley branches to Henley and Windsor.^[3][4]

History

The line was built by the Great Western Railway and engineered by Isambard Kingdom Brunel as a dual track line using a wider 7 ft (2,134 mm) broad gauge and was opened in stages between 1838 and 1841. The final section, between Chippenham and Bath, was opened on completion of the Box Tunnel in June 1841.^[5]

The alignment was so level and straight it was nicknamed "Brunel's billiard table". It was supplemented with a third rail for dual gauge operation, allowing standard gauge 4 ft 8 ¹⁄₂ in (1,435 mm) trains to also operate on the route, in stages between 1854 and 1875. Dual gauge was introduced as follows: London to Reading (October 1861), Reading to Didcot (December 1856), Didcot to Swindon (February 1872), Swindon to Thingley Junction, Chippenham (June 1874), Thingley Junction to Bathampton (March 1875), Bathampton to Bristol (June 1874), Bristol station area (May 1854). The broad gauge remained in use until 1892. Evidence of the original broad gauge can still be seen at many places where bridges are a wider than usual, or where tracks are ten feet apart instead of the usual six.^{[citation needed]}

The original dual tracks were widened to four in places, mainly in the east half, between 1877 and 1899: Paddington to Southall (October 1877), Southall to West Drayton (November 1878), West Drayton to Slough (June 1879), Slough to east side of Maidenhead Bridge (September 1884), Maidenhead Bridge to Reading (June 1893), Reading station (1899), Reading to Pangbourne (July 1893), Pangbourne to Cholsey and Moulsford (?), Cholsey and Moulsford to Didcot (December 1892); also short sections between Didcot and Swindon, and at Bristol.^{[citation needed]}

Following the Slough rail accident in 1900 when five passengers were killed, improved vacuum braking systems were used on locomotives and passenger rolling stock and Automatic Train Control (ATC) was introduced in 1908.

Further widenings of the line took place between 1903 and 1910 and more widening work took place between 1931 and 1932.^[6]

At the outbreak of World War I in 1914, the Great Western Railway was taken into government control, as were most major railways in Britain and were reorganised after the war into the "big four" companies, of which the Great Western Railway was one. The railways returned to direct government control during World War II before being nationalised to form British Railways (BR) in 1948.^{[relevant? – discuss]}

The line speed was upgraded in the 1970s to support the introduction of the InterCity 125 (HST).^[7]

In 1977 the Parliamentary Select Committee on Nationalised Industries recommended considering electrification of more of Britain's rail network, and by 1979 BR presented a range of options that included electrifying the line from Paddington to Swansea by 2000.^[8] Under the 1979–90 Conservative governments that succeeded the 1976–79 Labour government, the proposal was not implemented.

In August 2008 it was announced that a number of speed limits on the relief lines between Reading and London had been raised, so that 86% of the line could be used at 90 miles per hour (140 km/h).^[9]

Heritage

The route of the GWML includes dozens of listed buildings and structures, including tunnel portals, bridges and viaducts, stations, and associated hotels.^[10] Part of the route passes through and contributes to the Georgian Architecture of the City of Bath World Heritage Site; the path through Sydney Gardens has been described as a "piece of deliberate railway theatre by Brunel without parallel".^[11]Grade I listed structures on the line include London Paddington, Wharncliffe Viaduct, the 1839 Tudor gothic River Avon Bridge in Bristol, and Bristol Temple Meads station.^[12]

Route

The communities served by the Great Western main line include: West London (including Acton, Ealing, Hanwell, Southall, Hayes, Harlington and West Drayton); Iver; Langley; Slough; Burnham; Taplow; Maidenhead; Twyford; Reading; Tilehurst; Pangbourne; Goring-on-Thames; Streatley; Cholsey; Didcot; Swindon; Chippenham; Bath; Keynsham; and Bristol.

From London to Didcot, the line follows the Thames Valley, crossing the River Thames three times, including on the famous Maidenhead Railway Bridge. After Swindon, trains pass the Swindon Steam Railway Museum. From Wootton Bassett there are two different routes to Bristol, firstly via Box Tunnel and secondly via Bristol Parkway.

It is also possible to run via the Wessex Main Line, but this involves a reversal at Bradford Junction, so is only really suitable for multiple unit trains or via Reading to Bath via Newbury. Trains on the Great Western main line are sometimes diverted from Reading along the Reading to Taunton line, as far as Westbury, from where they can use the Wessex Main Line to reach either Chippenham, or Bath Spa. Beyond Bristol, some trains continue on the Bristol to Taunton Line to Weston-super-Mare or beyond.

The following routes are managed by Network Rail as part of the Great Western main line (Route 13):^[13] Didcot to Oxford and Worcester via the Cherwell Valley Line and Cotswold Line, Swindon to Cheltenham Spa via the Golden Valley Line, Swindon to Cardiff Central and Swansea via the South Wales Main Line, Cross Country Routes south of Birmingham and also all connecting branch lines.

Services

Main line and local services are provided by Great Western Railway (GWR). The stations served by trains between London Paddington and Bristol Temple Meads are: Slough, Reading, Didcot Parkway, Swindon, Chippenham, and Bath Spa. Some trains between London and Bristol do not call at Didcot Parkway and very few stop at Slough.

Fast trains from Paddington to London Heathrow Airport are operated by Heathrow Airport Holdings as the Heathrow Express. Local services on this route were previously jointly operated by GWR and BAA under the Heathrow Connect name.

CrossCountry operate trains between Reading and Oxford, using the Great Western main line as far as Didcot and South Western Railway operate a limited number of trains between Bath and Bristol.

Great Western Railway also operate a train between London Paddington – Cardiff Central every 30 minutes, with hourly extensions to Swansea. At Swansea/Cardiff there is a connecting Transport for Wales boat train to/from Fishguard Harbour for the Stena Line ferry to Rosslare Europort in Ireland. An integrated timetable is offered between London Paddington and Rosslare Europort with through ticketing available.^[14] Daytime and nocturnal journeys are offered in both directions daily (including Sundays). Additionally, 2–3 Great Western Railway trains continue to Pembroke Dock on weekends during the Summer season to connect with ferry services to Ireland.

Infrastructure

St James Railway Bridge, Bath

Between London and Didcot there are four tracks, two for each direction. The main lines are mostly used by the faster trains and are on the south side of the route. The relief lines on the north side are used for slower services and those that call at all stations, as only London Paddington, Slough, Maidenhead, Twyford, Reading and Didcot Parkway stations have platforms on the main lines (although a few others have main line platforms that can be used in an emergency). Between Didcot and Royal Wootton Bassett, a series of passing loops allow fast trains to overtake slower ones. This section is signalled for bi-directional running on each line but this facility is usually only used during engineering working or when there is significant disruption to traffic in one direction.^[15]

The summit of the line is at Swindon, and falls away in each direction: Swindon is 270 feet (82 m) above Paddington, and 292 feet (89 m) above Bristol Temple Meads. The maximum gradient between Paddington and Didcot is 1 in 1320 (0.75 ‰ or 0.075 %); between Didcot and Swindon it is 1 in 660 (1.5 ‰ or 0.15 %) but west of Swindon, gradients as steep as 1 in 100 (10 ‰ or 1 %) are found in places, such as Box Tunnel and to the east of Dauntsey.^[16][17]

The line is electrified between Paddington and Didcot Parkway using 25 kV AC overhead supply lines.^[18]

The line speed is 125 miles per hour (201 km/h).^[19] The relief lines from Paddington to Didcot are limited to 90 miles per hour (140 km/h) as far as Reading, and then 100 miles per hour (160 km/h) to Didcot. Lower restrictions apply at various locations.^[15] The line is one of two Network Rail-owned lines equipped with the Automatic Train Protection (ATP) system, the other being the Chiltern Main Line.^[20]

Tunnels, viaducts and major bridges

Major civil engineering structures on the Great Western main line include the following.^[21]

Line-side monitoring equipment

Line-side train monitoring equipment includes hot axle box detectors (HABD) and wheel impact load detectors (WILD) ‘Wheelchex’, these are located as follows.^[21][22]

Planned developments

Since 2011, the Great Western has been undergoing a £5 billion modernisation by Network Rail.^[23]

Reading railway station saw a major redevelopment with new platforms, a new entrance, footbridge and lifts; the work was completed a year ahead of schedule^[24] in July 2014.^[25][26]

Electrification from Airport Junction to the west

The Crossrail project covered electrification of the line from Airport Junction to Maidenhead and, following a number of announcements and delays, the government announced in March 2011 that it would electrify the line between London and Cardiff together with the section linking Bristol Parkway and Bristol Temple Meads.^[27][28] In July 2012, the government announced that the final portion of the Great Western, from Cardiff to Swansea, would be electrified.^[29]

Following delays to the original plan, and a major escalation of costs, the Conservative government announced in July 2017^[30] that, for the time being, the electrification would only be completed as far as Thingley Junction, two miles (3.2 km) west of Chippenham on the Swindon to Bristol Temple Meads section of the route. At the same time the Cardiff to Swansea section, that from Bristol Parkway to Bristol Temple Meads, and Didcot to Oxford were also postponed. The government argued that bi-mode trains will fill in the gaps pending completion of electrification, although the Class 800 trains are much slower in diesel mode than under electric power. The electrification as far as Didcot Parkway was completed in December 2017, and to Bristol Parkway and Newbury in December 2018.

In addition to allowing Crossrail services with the new Class 345 EMUs, the electrification allowed the introduction of Class 387 EMUs by GWR. It was originally planned to bring second-hand Class 365s from Great Northern after the arrival of their new Class 700 trains^[31] but it was later decided to order new Class 387s for GWR instead. Eight were delivered during 2016, with more on order to bring the total to 45. Some of the Class 165 and Class 166 DMUs currently used by GWR for Thames Valley services will be displaced to services on the lines around Cardiff and Bristol.^[32]

The line will also be used by the new Hitachi Super Express high speed trains – the Class 800s and Class 802s – which will gradually replace the InterCity 125 and Class 180 sets currently used for the long-distance services.

Other proposals

Network Rail plans to install European Rail Traffic Management System (ERTMS) in-cab signalling on the Great Western line;^[33][34] this is a pre-requisite for the Super Express trains to run at 140 mph (225 km/h).^[35] Some or all of the resignalling work will be undertaken during the electrification work.^[33]

Further capacity improvements are also scheduled at Swindon, adding to recent changes and the new Platform 4.

Crossrail services are planned to terminate at Reading. Some of the current suburban services into London Paddington are planned to be transferred to the new Crossrail service, which will in turn free up some surface-level capacity at London Paddington.^[33]

Other more distant aspirations include resignalling and capacity improvements at Reading; the provision of four continuous tracks between Didcot and Swindon (including a grade-separated junction at Milton, where westbound relief line switches from the north side of the line to the south); and resignalling between Bath and Bristol to enable trains to run closer together.

Access to Heathrow Airport from the west remains an aspiration and the 2009 Heathrow Airtrack scheme, abandoned in 2011, proposed a route south of the Great Western main line to link the airport with Reading. Plans for electrification of the line will make it easier to access Heathrow from Reading, since lack of electrification between Reading station and Airport Junction (near West Drayton station) was a limiting factor.^[33] Plans under consideration in 2014 included new tunnels between Heathrow and Langley.^[36]

Network Rail intends to replace the ATP system with ETCS – Level 2^[37] from 2017 to 2035 along with the introduction of the new IEP trains.

Signalling Solutions is to resignal the 12 miles (19 km) from Paddington to West Drayton, including the Airport branch, as part of the Crossrail project.^[38]

Calls for station reopenings

There are calls for the reintroduction of Corsham station due to recent growth of the town.^[39] The original station was closed to passengers in 1965.

A local group is campaigning for the reopening of Saltford station between Bath and Bristol, to coincide with electrification.^[40]

There have also been calls to reopen the former Wantage Road station.^[41]Oxfordshire County Council include a proposal for a new station to serve for Wantage and Grove in their 2015-2031 local transport plan.^[42]

Major incidents

• 
  Slough rail accident - 16 June 1900 - An express train from Paddington to Falmouth Docks ran through two sets of signals at danger and collided with a local train heading for Windsor. Five passengers were killed and 35 seriously injured.


• 
  Ealing rail crash - 19 December 1973 - A train from Paddington to Oxford derailed after a loose battery box cover on the Class 52 "Western" locomotive hauling the train struck lineside equipment, causing a set of points to move under the train. Ten passengers were killed and 94 injured.


• 
  Southall rail crash - 19 September 1997 - An InterCity 125 service from Swansea to Paddington, operated by Great Western Trains, failed to stop at a red signal and collided with a freight train entering Southall goods yard. Seven people were killed and 139 were injured. The incident severely damaged public confidence in the safety of the rail system. It was found that the train's AWS was faulty, and the driver had been distracted (he had bent down to pack his bag). Great Western Trains was fined £1.5 million for violations of health and safety law in connection with the accident.


• 
  Ladbroke Grove rail crash - 5 October 1999 - A Thames Trains service from Paddington to Bedwyn passed a signal at danger at the gantry protecting a main set of (crossover) points between the one-way and bi-directionally used lines. The train ran the wrong way down the line and was hit head-on by a First Great Western HST service from Cheltenham Spa to Paddington at a closing speed of approximately 130 miles per hour (210 km/h). 31 people died, including both drivers, with more than 520 people injured. Thames Trains was fined £2 million for violations of health and safety law.^[43]Network Rail pleaded guilty to charges under the Health and Safety at Work Act 1974 in relation to the accident. It was subsequently fined £4 million and was also ordered to pay £225,000 in costs.^[44]

Notes

The reference for the route map diagram is:-
Jowett, Alan (March 1989). Jowett's Railway Atlas of Great Britain and Ireland: From Pre-Grouping to the Present Day (1st ed.). Sparkford: Patrick Stephens Ltd. pp. 113, 115a, 116, 118b, 118d, 120, 124–25. ISBN 978-1-85260-086-0. OCLC 22311137..mw-parser-output cite.citationfont-style:inherit.mw-parser-output .citation qquotes:"""""""'""'".mw-parser-output .citation .cs1-lock-free abackground:url("//upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center.mw-parser-output .citation .cs1-lock-limited a,.mw-parser-output .citation .cs1-lock-registration abackground:url("//upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center.mw-parser-output .citation .cs1-lock-subscription abackground:url("//upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registrationcolor:#555.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration spanborder-bottom:1px dotted;cursor:help.mw-parser-output .cs1-ws-icon abackground:url("//upload.wikimedia.org/wikipedia/commons/thumb/4/4c/Wikisource-logo.svg/12px-Wikisource-logo.svg.png")no-repeat;background-position:right .1em center.mw-parser-output code.cs1-codecolor:inherit;background:inherit;border:inherit;padding:inherit.mw-parser-output .cs1-hidden-errordisplay:none;font-size:100%.mw-parser-output .cs1-visible-errorfont-size:100%.mw-parser-output .cs1-maintdisplay:none;color:#33aa33;margin-left:0.3em.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-formatfont-size:95%.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-leftpadding-left:0.2em.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-rightpadding-right:0.2em

References

Sources

• 
  BR Main Line Gradient Profiles: The Age of Steam. Hersham: Ian Allan. January 2003 [1966]. ISBN 0-7110-0875-2. 0301/A.
  


• 
  MacDermot, E.T. (1927). History of the Great Western Railway, vol. I: 1833-1863. Paddington: Great Western Railway.
  


• 
  Sanderson, Joanna; Pollard, Richard; Thorne, Robert; Hradsky, Robert; Bevan, Robert; Howell, Jason; Bogdanovich, Boris; Harrison, Tim (April 2012). Meade, Susannah; Craggs, Patricia, eds. "Great Western Main Line Route Structures Gazetteer - Prepared for Network Rail". Alan Baxter & Associates LLP.
  

Further reading

• 
  Pre-grouping Atlas and Gazetteer. Shepperton: Ian Allan Limited. 1976. ISBN 0-7110-0320-3.
  


• 
  MacDermot, E T (1927). History of the Great Western Railway, volume I 1833-1863. London: Great Western Railway.
  


• 
  MacDermot, E T (1931). History of the Great Western Railway, volume II 1863-1921. London: Great Western Railway.
  

External links

Wikimedia Commons has media related to Great Western Main Line.

Route map:

• 
  Paddington, Reading General, Didcot and Milton (British Railways in the 1960s Sectional Appendix Extract)


• 
  Reading, Main Line West and Bedwyn (British Railways in the 1960s Sectional Appendix Extract)