View source for Great Western Main Line

{{short description|Principal main line railway in England}}
{{distinguish|West Coast Main Line|West of England line}}
{{Use British English|date=July 2015}}
{{Use dmy dates|date=June 2021}}
{{Infobox rail line
| box_width                       = 
| name                            = Great Western Main Line
| color                           = 
| image                           = Brunel's railway bridge at Maidenhead from the Thames Path National Trail, geograph 5893373 by Dave Kelly.jpg
| image_width                     = 
| caption                         = [[Maidenhead Railway Bridge]] carrying the line over the [[River Thames]].
| type                            = [[Commuter rail]], [[Higher-speed rail]]<ref>{{cite news |last1 = Bowen |first1 = Douglas John |title = Hitachi Rail Europe taps Huber+Suhner |url = http://www.railwayage.com/index.php/communications/hitachi-rail-europe-taps-huber-suhner.html |access-date = 2 December 2014 |work = Railway Age |date = 1 December 2014 |archive-date = 4 March 2016 |archive-url = https://web.archive.org/web/20160304212329/http://www.railwayage.com/index.php/communications/hitachi-rail-europe-taps-huber-suhner.html |url-status = dead}}</ref>
| system                          = [[National Rail]]
| status                          = Operational
| locale                          = {{ubl|[[Greater London]]|[[South East England]]|[[South West England]]}}
| start                           = [[Paddington station|London Paddington]]
| end                             = {{Stnlnk|Bristol Temple Meads}}
| stations                        = 25
| daily_ridership                 = 
| open                            = 30 June 1841 (complete line)
| owner                           = [[Network Rail]]
| operator                        = {{ubl|[[Great Western Railway (train operating company)|Great Western Railway]],|[[Elizabeth line]],|[[Heathrow Express]],|[[CrossCountry]]}}
| depot                           = {{ubl|[[North Pole depot|North Pole]],|[[Reading TMD|Reading]],|[[St Philip's Marsh depot|St Philip's Marsh]]}}
| stock                           = {{ubl|{{brc|158}}|{{brc|159}}|{{brc|165}}|{{brc|166}}|{{brc|220}}|{{brc|221}}|{{brc|345}}|{{brc|387}}|{{brc|800}}|{{brc|802}}}}
| linelength                      = {{convert|118|mi|19|ch|km|2|abbr=out}}
| tracks                          = Four (London to Didcot),<br />two (Didcot to Bristol)
| gauge                           = {{track gauge|uksg|lk=on}}
| old_gauge                       = {{track gauge|7ft0.25in|lk=on}}
| minradius                       = 
| electrification                 = [[25 kV AC|25 kV 50 hz AC]] [[Overhead line|OLE]] (London to Chippenham)
| speed                           = {{convert|125|mph|abbr=on|round=10}}
| signalling                      = [[Automatic Warning System|AWS]], [[Train Protection & Warning System|TPWS]], [[Automatic Train Protection (United Kingdom)|ATP]]
| map                             = [[File:Great Western Main Line map.png|321px]]
| map_state                       = uncollapsed
}}
{{Great Western Main Line diagram}}
The '''Great Western Main Line''' ('''GWML''') is a [[main line (railway)|main line]] [[railway]] in England that runs between [[Paddington railway station|London Paddington]] and {{stnlnk|Bristol Temple Meads}}. It connects to other main lines such as those from [[Reading to Taunton line|Reading to Penzance]] and [[South Wales Main Line|Swindon to Swansea]]. The GWML is presently a part of the national rail system managed by [[Network Rail]], while the majority of passenger services upon it are provided by the current [[Great Western Railway (train operating company)|Great Western Railway]] franchise.

The GWML was built by the original [[Great Western Railway]] company between 1838 and 1841, as a dual track line in the {{track gauge|84in|lk=on}} [[broad gauge]]. The broad gauge remained in use until 1892, after which standard gauge track has been exclusively used. Between 1877 and 1932, many sections of the GWML were widened to four tracks. During 1908, [[Automatic train control#United Kingdom|Automatic Train Control]] (ATC) was introduced as a safety measure. In 1948, the Great Western Railway, and thus the GWML, was merged into the [[Western Region of British Railways]].

During the 1970s, the GWML was upgraded to support higher line speeds, as a result of which many sections permitted {{cvt|125|mph|km/h}} operations, enabling the newly introduced [[InterCity 125]] high speed train (HST) to make faster journeys. [[British Rail]] proposed widespread electrification of the line in the late 1970s, although this was not speedily implemented. During the mid-1990s, a stretch of the GWML between London Paddington and [[Hayes & Harlington railway station|Hayes & Harlington]] was electrified using {{nowrap|[[25 kV AC]]}} overhead lines for the [[Heathrow Express]]. Further, although not total, electrification was carried out during the 2010s; this permitted the replacement of diesel-powered trains such as the InterCity 125 and {{brc|180}} with electric and [[Electro-diesel multiple unit|bi-mode train sets]] such as the [[Intercity Express Programme|Hitachi Super Express]] high speed trains, specifically the {{brc|800}} and {{brc|802}}. Due to budget overruns, the British government deferred electrification of the section through [[Bath Spa railway station|Bath Spa]] from [[Royal Wootton Bassett]] to [[Bristol]] in 2016.

The route includes dozens of [[listed building]]s and structures, including tunnel portals, bridges and viaducts, stations, and associated hotels. Presently, the GWML is electrified between London Paddington and Royal Wootton Bassett. In the long term, Network Rail plans to install [[European Rail Traffic Management System]] (ERTMS) in-cab signalling across the entire line.

==History==
===Construction===
The construction of what would become the GWML was motivated by several factors, one of the more influential being the sizeable merchant community of Bristol, which keenly advocated for such a railway to be built to help maintain the city's position as the second port of the country as well as the chief one for American trade.<ref>{{Cite book |last = Channon |first = Geoffrey |url = https://archive.org/details/bha062 |title = Bristol and the Promotion of the Great Western Railway, 1835 |isbn = 0-901388-45-9 |publisher = Bristol Historical Association |year = 1985 |location = Bristol, UK |publication-date = 1985 |language = en-GB}}</ref> More specifically, fearing rising competition from [[Liverpool]] and railway developments to its favour, the sought railway was to be preferably built to superior standards as to out-perform any of the lines serving the [[North West England|North West of England]].<ref name="MacD1-1">{{harvnb|MacDermot|1927|loc=chapter 1}}</ref> Thus, the line built by the [[Great Western Railway]] and engineered by [[Isambard Kingdom Brunel]] was originally a dual track line using a wider {{track gauge|84in|lk=on}} [[broad gauge]].<ref>{{cite journal |last = Clark |first = GT |author-link = G. T. Clark |title = The Birth and Growth of the Broad Gauge |journal = Gentleman's Magazine |issue = 279 |pages = 489–506 |year = 1895}}</ref> The line's construction costs were considerably higher due to the use of this broad gauge.<ref name = "first hsr2019"/>

The route of the GWML includes dozens of [[listed building]]s and structures, including tunnel portals, bridges and viaducts, stations, and associated hotels.{{sfn|Sanderson | Pollard | Thorne | Hradsky |2012}} 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".{{sfn|Sanderson | Pollard | Thorne | Hradsky |2012|loc = MLN1 10605, MLN1 10605, MLN1 10605, MLN1 10610, MLN1 10614, MLN1 10618}} [[Grade I]] listed structures on the line include [[London Paddington]], [[Wharncliffe Viaduct]], the 1839 Tudor gothic [[Avon Bridge|River Avon Bridge]] in Bristol, and [[Bristol Temple Meads railway station|Bristol Temple Meads station]].{{sfn|Sanderson | Pollard | Thorne | Hradsky |2012| loc = MLN1 0000 , MLN1 0742, MLN1 11725, MLN1 11826 }}<ref name = "first hsr2019"/>

The line was opened in stages between 1838 and 1841.<ref>{{harvnb|MacDermot|1927|pp=130–131}}</ref> The first section, between Paddington and [[Taplow railway station|Maidenhead Bridge]] opened on 4 June 1838; the final section, between Chippenham and Bath, was opened on completion of the [[Box Tunnel]], the longest railway tunnel driven by that time, in June 1841.<ref>{{cite web |url = http://www.british-history.ac.uk/vch/wilts/vol4/pp280-293 |title = Victoria County History: Wiltshire: Vol 4: Railways |year = 1959 |editor-last = Crittall |editor-first = Elizabeth |website = british-history.ac.uk |publisher = University of London |access-date = 27 December 2017 |archive-date = 16 July 2021 |archive-url = https://web.archive.org/web/20210716084149/https://www.british-history.ac.uk/vch/wilts/vol4/pp280-293 |url-status = live |language = en-GB}}</ref><ref>{{cite book |last = Swift |first = Andrew |title = The Ringing Grooves of Change |year = 2006 |publisher = Akeman Press |isbn = 0-9546138-5-6 |pages = 215–249 }}</ref> The line's alignment was so level and straight it was nicknamed "Brunel's billiard table".<ref name = "first hsr2019">{{cite magazine |title = The Great Western: the world's first high speed railway |first = Gareth |last = Dennis |magazine = Rail |issue = 873 |date = 27 February 2019}}</ref>

===Changes under the Great Western Railway===
The track was supplemented with a third rail for [[dual gauge]] operation, allowing standard gauge {{track gauge|uksg}} trains to also operate on the route, in stages between 1854 and 1875. Dual gauge was introduced as follows: London to [[Reading railway station|Reading]] (October 1861), Reading to {{rws|Didcot}} (December 1856), Didcot to {{rws|Swindon}} (February 1872), Swindon to Thingley Junction, {{rws|Chippenham}} (June 1874), Thingley Junction to {{rws|Bathampton}} (March 1875), Bathampton to Bristol (June 1874), Bristol station area (May 1854). The broad gauge remained in use until 1892, at which point the last 500 miles of track were converted to standard gauge.<ref name = "first hsr2019"/><ref>{{cite book |last = Clinker |first = C. R. |title = New light on the Gauge Conversion |year = 1978 |publisher = Avon-Anglia |location = Bristol, UK |isbn = 0-905466-12-8 |pages = 15–16 }}</ref>

Between 1877 and 1899, the original dual tracks were widened to four in numerous places, mainly in the east half of the line: Paddington to {{rws|Southall}} (October 1877), Southall to {{rws|West Drayton}} (November 1878), West Drayton to {{rws|Slough}} (June 1879), Slough to east side of [[Maidenhead Railway Bridge|Maidenhead Bridge]] (September 1884), Maidenhead Bridge to {{rws|Reading}} (June 1893), Reading station (1899), Reading to {{rws|Pangbourne}} (July 1893), Pangbourne to [[Cholsey railway station|Cholsey and Moulsford]] (June 1894), Cholsey and Moulsford to [[Didcot Parkway railway station|Didcot]] (December 1892); also short sections between Didcot and Swindon, and at Bristol.{{citation needed|date=December 2016}}

Following the [[Slough rail accident]] of 1900, in which five passengers were killed, improved [[vacuum brake|vacuum braking]] systems were used on locomotives and passenger rolling stock; furthermore, [[Automatic train control#United Kingdom|Automatic Train Control]] (ATC) was introduced in 1908.<ref name="Derail">{{cite book |last = Faith |first = Nicholas |date = 2000 |title = Derail: Why Trains Crash |location = London, UK |publisher = [[Channel 4]] |page = 53 |isbn = 9780752271651}}</ref>

Further widenings of the line took place between 1903 and 1910; another round of widening works occurred between 1931 and 1932.{{sfn|Sanderson | Pollard | Thorne | Hradsky |2012| page = 6 }} By the 1930s, trains traversing the GWML were reportedly attaining the highest average speeds in the world.<ref name = "first hsr2019"/>

A legacy of the broad gauge was that trains for some routes could be built slightly wider than was normal in Britain; examples included the 1929-built ''[[GWR Super Saloons|Super Saloons]]'' used on the [[boat train]] services that conveyed transatlantic passengers to London in luxury.<ref>{{cite book |last = Harris |first = Michael |title = Great Western Coaches From 1890 |publisher = David and Charles |year = 1985 |edition = 3rd |location = Newton Abbot |isbn = 0-7153-8050-8 |page = 83}}</ref> When the company celebrated its centenary during 1935, new "Centenary" carriages were built for the Cornish Riviera Express, which again made full use of the wider [[loading gauge]] on that route.<ref>{{harvnb|Harris|1985|page=95}}</ref>

At the outbreak of the [[First World War]] in 1914, the Great Western Railway, and thus the GWML, was taken into government control, as were most major railways in Britain. After the conflict, the companies were reorganised into the [[Big Four (British railway companies)|"big four" companies]], of which the Great Western Railway was one. The railways, including the GWML, returned to direct government control during the [[Second World War]] before being [[nationalisation|nationalised]] to form [[British Rail]]ways (BR) in 1948, thus bringing the line into public ownership.<ref>{{cite magazine |date = January–February 1948 |title = British Railways |magazine = [[The Railway Magazine]] |location = Westminster, UK |publisher = Railway Publishing Company |publication-date = 1 January 1948 |volume = 94 |issue = 573 |page = 72 |language = en-GB}}</ref><ref>{{cite magazine |date = March–April 1948 |title = The Minor British Railways and the Joint Lines |magazine = [[The Railway Magazine]] |location = Westminster, UK |publisher = Railway Publishing Company |publication-date = 1 March 1948 |volume = 94 |issue = 574 |page = 126 |language = en-GB}}</ref>

===British Rail era===
Unlike the other BR regions, which introduced [[diesel-electric]] locomotives, the [[Western Region of British Railways|Western Region]], to which the GWML belonged, decided to procure a complete range of [[diesel-hydraulic]] locomotives to fulfil its [[List of British Rail power classifications|type 1 to type 4]] power requirements. These included the [[British Rail Class 42|''Warship'']] locomotives, which were based on proven [[West German]] designs, the British-designed [[British Rail Class 14|Class 14]], [[British Rail Class 35|''Hymek'']] and [[British Rail Class 52|''Western'']] types. However, these were all eventually withdrawn and replaced with more standard British Rail diesel-electric classes such as the [[British Rail Class 37|Class 37]] and [[British Rail Class 47|Class 47]].

During the 1970s, the line speed of the GWML was upgraded to permit faster operations; this work was in preparation for the introduction of the [[InterCity 125]] high speed train (HST).<ref name='EarlyHighspeedBR'>{{cite journal |title = High speed track on the Western Region of British Railways |last = Collins |first = R.J. |journal = Proceedings of the Institution of Civil Engineers |year = 1978 |volume = 64 |issue = 2 |pages = 207–225 |publisher = [[Institution of Civil Engineers]] |doi = 10.1680/iicep.1978.2755 |language = en-GB}}</ref><ref name=bbc1976>{{cite news |title = New train speeds into service |url = http://news.bbc.co.uk/onthisday/hi/dates/stories/october/4/newsid_2486000/2486817.stm |access-date = 15 May 2019 |work = BBC News |date = 4 October 1976 |language = en-GB}}</ref> The HST brought about considerable improvements in service and reduced journey times.<ref>{{Cite news |last1 = Owen |first1 = A.D. |last2 = Phillips |first2 = G.D.A. |publisher = [[University of Bath]] |title = The Characteristics of Railway passenger demand |page = 234 |url = http://www.bath.ac.uk/e-journals/jtep/pdf/Volume_XX1_No_3_231-253.pdf |language = en-GB}}</ref><ref>{{cite news |url = http://news.bbc.co.uk/1/hi/england/berkshire/5407016.stm |title = High Speed Train marks 30 years |work = BBC News |access-date = 29 April 2009 |date = 4 October 2006 |first = Joe |last = Campbell |language = en-GB}}</ref>

In 1977, the Parliamentary Select Committee on Nationalised Industries recommended considering electrification of more of Britain's rail network and, by 1979, British Rail had presented a range of options that included electrifying the line from Paddington to Swansea by 2000.<ref>{{cite book |title = Railway Electrification |date = Winter 1979 |publisher = [[British Railways Board]] (Central Publicity Unit) |pages = 0–2, 8}}</ref> Under the [[Premiership of Margaret Thatcher|1979–90 Conservative governments]] that succeeded the [[Callaghan ministry|1976–79 Labour government]], the proposal was not implemented.

In the mid-1990s, the line between London Paddington and [[Hayes & Harlington railway station|Hayes & Harlington]] was electrified as part of the [[Heathrow Express]] scheme, which was officially launched in June 1998.<ref>{{Cite web |title = Heathrow Express |url = https://www.railway-technology.com/projects/heathrow-express/ |access-date = 30 June 2020 |website = Railway Technology |language = en-GB |archive-date = 15 August 2018 |archive-url = https://web.archive.org/web/20180815045612/https://www.railway-technology.com/projects/heathrow-express/ |url-status = live}}</ref><ref>{{cite news |date = 23 June 1998 |title = Heathrow Express takes off |url = http://news.bbc.co.uk/1/hi/uk/118180.stm |url-status = live |archive-url = https://web.archive.org/web/20201220201437/http://news.bbc.co.uk/2/hi/uk_news/118180.stm |archive-date = 20 December 2020 |access-date = 6 August 2016 |work = BBC News |language = en-GB}}</ref>

===Privatisation era===
As part of the [[privatisation of British Rail]], the Great Western [[InterCity (British Rail)|InterCity]] franchise was awarded by the [[Director of Passenger Rail Franchising]] to [[Great Western Holdings]] in December 1995, and it began operations on 4 February 1996.<ref>{{Cite news |url = https://www.theguardian.com/uk/1997/sep/20/alexbellos |title=The passenger train |last1 = Bellos |first1 = Alex |date = 20 September 1997 |work = The Guardian |location = London, UK |access-date=4 September 2020 |language = en-GB}}</ref><ref>{{cite web |url = http://www.parliament.uk/documents/commons/lib/research/rp99/rp99-080.pdf |title = Railway Organisations Research Paper 99/80 |publisher = House of Commons Library |date=20 September 1999 |language = en-GB}}</ref> Via multiple contract extensions, this operator, which currently trades as [[Great Western Railway (train operating company)|Great Western Railway]] has been the primary operator of passenger services on the GWML for multiple decades.<ref>{{cite press release |url = https://www.gov.uk/government/news/critical-rail-services-protected-in-new-deals-for-gwr-and-southeastern |title = Critical rail services protected in new GWR and Southeastern |publisher = Department for Transport |date = 30 March 2020}}</ref><ref>{{cite magazine |archive-url = https://web.archive.org/web/20200401051953/https://www.railwaygazette.com/uk/firstgroup-says-new-great-western-contract-has-appropriate-balance-of-risk-and-reward/56134.article |archive-date = 1 April 2020 |url = https://www.railwaygazette.com/uk/firstgroup-says-new-great-western-contract-has-appropriate-balance-of-risk-and-reward/56134.article |title = FirstGroup says new Great Western contract has appropriate balance of risk and reward |magazine = Railway Gazette International |location = London, UK |date = 30 March 2020}}</ref><ref>{{cite web |url = https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1122644/first-greater-western-ltd-2022-nrc.pdf |title = First Greater Western Limited 2022 national rail contract |publisher = Department for Transport |date = 14 June 2022 |access-date = 5 March 2023}}</ref>

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 {{cvt|90|mph}}.<ref name="First Great Western Customer Panel">{{cite web |url = http://www.firstgreatwestern.co.uk/Documents/Custom/Customer%20panel/East%20Customer%20Panel%209.10.08%20minutes%20-%20WEBSITE.pdf |title = First Great Western Customer Panel |access-date = 24 November 2008 |publisher = [[First Great Western]] |archive-date = 11 October 2010 |archive-url = https://web.archive.org/web/20101011164756/http://firstgreatwestern.co.uk/Documents/Custom/Customer%20panel/East%20Customer%20Panel%209.10.08%20minutes%20-%20WEBSITE.pdf |url-status = dead |language = en-GB}}</ref>

By 2019, the partial electrification of the GWML permitted the replacement of InterCity 125 and {{brc|180}} sets by new [[Intercity Express Programme|Hitachi Super Express]] high speed trains – the {{brc|800}} and {{brc|802}}. The procurement programme for these trains, known as the [[Intercity Express Programme]], was highly impacted by the GWML's electrification scheme, particularly the abandonment of diesel-only trains in favour of bi-mode trains, which were elongated and outfitted with a second transformer to maximise their use of the electrified sections.{{sfn|Foster|2010|pp=14-15|loc = The IEP}}{{sfn|Foster|2010a|pp=26—27}} The electrification of the line also allowed the introduction of other rolling stock, such as {{brc|387}} [[electric multiple units]], to conduct shorter-distance services.<ref>{{Cite web |date = 24 March 2015 |title = Derby to build new trains for First Great Western |url = http://www.railnews.co.uk/news/2015/03/24-derby-to-build-new-trains.html |access-date = 2 January 2017 |website = railnews.co.uk |archive-date = 16 July 2021 |archive-url = https://web.archive.org/web/20210716084228/https://www.railnews.co.uk/news/2015/03/24-derby-to-build-new-trains.html |url-status = live |language = en-GB}}</ref>

==Route==
The main communities served by the Great Western Main Line are [[London|West London]] (including [[Acton, London|Acton]], [[Ealing]], [[Hanwell]], [[Southall]], [[Hayes, Hillingdon|Hayes]], [[Harlington, London|Harlington]] and [[West Drayton]]), [[Iver]], [[Langley, Slough|Langley]], [[Slough]], [[Burnham, Buckinghamshire|Burnham]], [[Taplow]], [[Maidenhead]], [[Twyford, Berkshire|Twyford]], [[Reading, Berkshire|Reading]], [[Tilehurst]], [[Pangbourne]], [[Goring-on-Thames]], [[Streatley, Berkshire|Streatley]]; [[Cholsey]], [[Didcot]], [[Swindon]], [[Chippenham]], [[Bath, Somerset|Bath]], [[Keynsham]] and [[Bristol]].<ref>{{Cite web |url = https://www.networkrail.co.uk/wp-content/uploads/2016/11/Network-Specification-2016-Western-Route.pdf |title = Western Route specification |access-date = 13 March 2020 |archive-date = 16 July 2021 |archive-url = https://web.archive.org/web/20210716084203/https://www.networkrail.co.uk/wp-content/uploads/2016/11/Network-Specification-2016-Western-Route.pdf |url-status = live}}</ref>

From London to Didcot, the line follows the [[Thames Valley]], crossing the River Thames three times, including on the [[Maidenhead Railway Bridge]]. Between Chippenham and Bath the line passes through [[Box Tunnel]], and then follows the valley of the [[River Avon (Bristol)|River Avon]].

A junction west of Swindon allows trains to reach Bristol by an alternative route along the [[South Wales Main Line]]. Other diversionary routes exist between Chippenham and Bath via {{stnlnk|Melksham}} and the [[Wessex Main Line]], although this involves a reversal at Bradford Junction; and from Reading to Bath via the [[Reading–Taunton line]].

==Services==
Services of three [[train operating companies]] use the line:

* [[Great Western Railway (train operating company)|Great Western Railway]] (GWR) operates most services:<ref>{{Cite web |title=Train Times |work=Great Western Railway |date=18 May 2025 |access-date=20 May 2025 |url= https://www.gwr.com/travel-information/train-times}}</ref>
** [[Inter-city rail|Inter-city]] trains run between London Paddington and Bristol Temple Meads, via Reading, Didcot Parkway, Swindon, Chippenham and Bath Spa; some services do not call at Didcot Parkway.
** Inter-city services between London Paddington – Cardiff Central operate every 30{{nbsp}}minutes, with hourly extensions to Swansea. At Swansea/Cardiff, there is a connecting [[Transport for Wales Rail|Transport for Wales]]' boat train to/from [[Fishguard Harbour railway station|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.<ref>{{cite web |url = http://www.stenaline.ie/ferry/rail-and-sail/fishguard/ |title = Sail and Rail to Britain – Train and Ferry Travel to England & Wales – Stena Line |publisher = Stenaline.ie |access-date = 16 September 2013 |archive-url = https://web.archive.org/web/20131203005619/http://www.stenaline.ie/ferry/rail-and-sail/fishguard/ |archive-date = 3 December 2013 |url-status = dead |language = en}}</ref> Daytime and nocturnal journeys are offered in both directions daily.
** [[Heathrow Express]] trains from Paddington to [[London Heathrow Airport]], on behalf of [[Heathrow Airport Holdings]].<ref>{{Cite magazine |url=https://www.railwaygazette.com/gwr-to-manage-heathrow-express-service/46205.article |title=GWR to manage Heathrow Express service |magazine=Railway Gazette International |access-date=3 August 2024 |archive-date=3 June 2020 |archive-url=https://web.archive.org/web/20200603162618/https://www.railwaygazette.com/gwr-to-manage-heathrow-express-service/46205.article |url-status=live}}</ref>

* [[Elizabeth line]] services run on the Great Western Main Line between London and Reading.<ref>{{Cite web |title=Elizabeth line timetables |work=Transport for London |date=18 May 2025 |access-date=20 May 2025 |url= https://tfl.gov.uk/modes/elizabeth-line/elizabeth-line-timetables}}</ref>

* [[CrossCountry]] operates long-distance trains using the GWML between Reading and Didcot Parkway.<ref>{{Cite web |title=Train Timetables |work=CrossCountry |date=18 May 2025 |access-date=20 May 2025 |url= https://www.crosscountrytrains.co.uk/travel-updates-information/train-timetables}}</ref>

==Infrastructure==
[[File:St James Railway Bridge, Bath.jpg|thumb|right|St James Railway Bridge, Bath]]
There are four tracks between London and Didcot, two in 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.<ref name=2007plans/>

The summit of the line is at Swindon and falls away in each direction: Swindon is {{convert|270|ft|m}} above Paddington and {{convert|292|ft|m}} above Bristol Temple Meads. The maximum [[grade (slope)|gradient]] between Paddington and Didcot is 1 in 1320 (0.75{{nbsp}}[[‰]] or 0.075[[Percent sign|%]]); between Didcot and Swindon it is 1 in 660 (1.5{{nbsp}}‰ or 0.15%), but west of Swindon, gradients as steep as 1 in 100 (10{{nbsp}}‰ or 1%) are found in places, such as [[Box Tunnel]] and to the east of {{stnlnk|Dauntsey}}.{{sfn|MacDermot|1927|pp=124, 127}}{{sfn|Gradient Profiles|2003|loc=figs. W1, W6}}

The line is electrified between Paddington and Langley Burrell (just east of Chippenham) using {{nowrap|[[25 kV AC]]}} overhead supply lines; the Reading to Taunton line (as far as Newbury) and the South Wales Main Line (as far as Cardiff Central) are also electrified.

The line speed is {{cvt|125|mph|km/h}}.<ref>{{cite web |title = About Great Western Main Line |url = http://www.agilitytrains.com/great-western-main-line |publisher = Agility Trains |access-date = 20 December 2015 |archive-url = https://web.archive.org/web/20151222115910/http://www.agilitytrains.com/great-western-main-line |archive-date = 22 December 2015 |url-status = dead |language = en-GB}}</ref> The relief lines from Paddington to Didcot are limited to {{cvt|90|mph|km/h}} as far as Reading, and then {{cvt|100|mph|km/h}} to Didcot. Lower restrictions apply at various locations.<ref name=2007plans>{{cite web |title = Route Plans 2007 Route 13 Great Western Main Line |url = http://www.networkrail.co.uk/browse_documents/BusinessPlan2007/PDF/Route_2013_Great_Western_Main_Line.pdf |publisher = Network Rail |access-date = 20 December 2015 |archive-url = https://web.archive.org/web/20120925215820/http://www.networkrail.co.uk/browse_documents/BusinessPlan2007/PDF/Route_2013_Great_Western_Main_Line.pdf |archive-date = 25 September 2012 |url-status = dead |language = en-GB}}</ref> 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]].<ref>{{cite web |title = Great Western Main Line ATP Pilot Scheme |url = http://www.traintesting.com/GWML%20ATP.htm |publisher = Train Testing |access-date = 20 December 2015 |archive-date = 23 December 2015 |archive-url = https://web.archive.org/web/20151223114737/http://www.traintesting.com/GWML%20ATP.htm |url-status = live}}</ref>

=== Tunnels, viaducts and major bridges ===
Major civil engineering structures on the Great Western Main Line include the following.<ref name=":0">{{Cite book |title = Railway Track Diagrams Book 3 Western |last = Bridge |first = Mike |publisher = Tackmaps |year = 2010 |isbn = 978-0-9549866-6-7 |location = Bradford on Avon, UK |language = en-GB |pages = 1–5}}</ref>
{| class="wikitable"
|+Tunnels, viaducts and major bridges on the Great Western Main Line
!Railway structure
!Length
!Distance from London Paddington
!Location
|-
|Subway Tunnel (LU)
|{{convert|117|yd|m}}
|{{convert|0|mi|67|chain|km}} – {{convert|0|mi|73|chain|km}}
|West of Royal Oak
|-
|Spring Bridge Road Car Park Tunnel
|{{convert|121|yd|m}}
|{{convert|5|mi|70|chain|km}} – {{convert|5|mi|76|chain|km}}
|West of [[Ealing Broadway station|Ealing Broadway]]
|-
|Hanwell Viaduct
|{{convert|44|yd|m}}
|{{convert|7|mi|35|chain|km}} –  {{convert|7|mi|38|chain|km}}
| rowspan="3" |West of [[Hanwell railway station|Hanwell]]
|-
|[[Wharncliffe Viaduct]]
|{{convert|297|yd|m}}
|{{convert|7|mi|43|chain|km}} – {{convert|7|mi|56|chain|km}}
|-
|Hanwell Bridge
|{{convert|4|chain|m}}
|{{convert|8|mi|00|chain|km}} – {{convert|8|mi|04|chain|km}}
|-
|[[Maidenhead Railway Bridge|Maidenhead Viaduct]] ([[River Thames]])
|{{convert|237|yd|m}}
|{{convert|23|mi|21|chain|km}} – {{convert|23|mi|32|chain|km}}
|East of [[Maidenhead railway station|Maidenhead]]
|-
|Seven Arch Viaduct
|{{convert|68|yd|m}}
|{{convert|31|mi|19|chain|km}} – {{convert|31|mi|22|chain|km}}
| rowspan="2" |West of [[Twyford railway station|Twyford]]
|-
|River Loddon Viaduct
|{{convert|70|yd|m}}
|{{convert|31|mi|43|chain|km}} – {{convert|31|mi|46|chain|km}}
|-
|Kennet Bridge ([[Kennet and Avon Canal|Kennet & Avon Canal]])
|{{convert|4|chain|m}}
|{{convert|34|mi|77|chain|km}} – {{convert|35|mi|01|chain|km}}
|East of [[Reading railway station|Reading]]
|-
|[[Gatehampton Railway Bridge|Gatehampton Viaduct]] (River Thames)
|{{convert|99|yd|m}}
|{{convert|44|mi|00|chain|km}} – {{convert|44|mi|05|chain|km}}
|East of [[Goring & Streatley railway station|Goring & Streatley]]
|-
|[[Moulsford Railway Bridge|Moulsford Viaduct]] (River Thames)
|{{convert|147|yd|m}}
|{{convert|47|mi|27|chain|km}} – {{convert|47|mi|34|chain|km}}
|East of [[Cholsey railway station|Cholsey]]
|-
|River Avon Viaduct
|{{convert|72|yd|m}}
|{{convert|90|mi|77|chain|km}} – {{convert|91|mi|00|chain|km}}
|East of [[Chippenham railway station|Chippenham]]
|-
|[[Chippenham viaduct]]
|{{convert|90|yd|m}}
|{{convert|94|mi|08|chain|km}} – {{convert|94|mi|13|chain|km}}
|West of Chippenham
|-
|[[Box Tunnel]]
|{{convert|1|mi|1452|yd|km}}
|{{convert|99|mi|12|chain|km}} – {{convert|100|mi|78|chain|km}}
| rowspan="2" |Between Chippenham and [[Bath Spa railway station|Bath Spa]]
|-
|Middle Hill Tunnel
|{{convert|198|yd|m}}
|{{convert|101|mi|39|chain|km}} – {{convert|101|mi|48|chain|km}}
|-
|Sydney Gardens East Tunnel
|{{convert|77|yd|m}}
|{{convert|106|mi|24|chain|km}} – {{convert|106|mi|28|chain|km}}
| rowspan="3" |East of Bath Spa
|-
|Sydney Gardens West Tunnel
|{{convert|99|yd|m}}
|{{convert|106|mi|29|chain|km}} – {{convert|106|mi|33|chain|km}}
|-
|Dolemeads Viaduct
|{{convert|355|yd|m}}
|{{convert|106|mi|49|chain|km}} – {{convert|106|mi|60|chain|km}}
|-
|Arches and St James Viaduct
|{{convert|600|yd|m}}
|{{convert|106|mi|68|chain|km}} – {{convert|107|mi|20|chain|km}}
|West of Bath Spa
|-
|Twerton Viaduct
|{{convert|638|yd|m}}
|{{convert|108|mi|29|chain|km}} – {{convert|108|mi|58|chain|km}}
| rowspan="4" |Between [[Oldfield Park railway station|Oldfield Park]] and [[Keynsham railway station|Keynsham]]
|-
|Twerton Short Tunnel
|{{convert|45|yd|m}}
|{{convert|108|mi|70|chain|km}} – {{convert|108|mi|72|chain|km}}
|-
|Twerton Long Tunnel
|{{convert|264|yd|m}}
|{{convert|109|mi|03|chain|km}} – {{convert|109|mi|15|chain|km}}
|-
|Saltford Tunnel
|{{convert|176|yd|m}}
|{{convert|111|mi|57|chain|km}} – {{convert|111|mi|65|chain|km}}
|-
|St Annes Park Arches Viaduct
|{{convert|4|chain|m}}
|{{convert|115|mi|25|chain|km}} – {{convert|115|mi|29|chain|km}}
| rowspan="7" |Between Keynsham

and [[Bristol Temple Meads railway station|Bristol Temple Meads]]
|-
|St Annes Park No.3 Tunnel (or Foxes Wood Tunnel)
|{{convert|1017|yd|m}}
|{{convert|115|mi|58|chain|km}} – {{convert|116|mi|25|chain|km}}
|-
|St Annes Park or (Bristol) No.2 Tunnel
|{{convert|154|yd|m}}
|{{convert|116|mi|41|chain|km}} – {{convert|116|mi|48|chain|km}}
|-
|Main River Viaduct (River Avon)
|{{convert|108|yd|m}}
|c. {{convert|117|mi|24|chain|km}}
|-
|Main Down Viaduct (River Avon)
|{{convert|141|yd|m}}
|{{convert|117|mi|21|chain|km}} – {{convert|117|mi|27|chain|km}}
|-
|The Feeder
|
|{{convert|117|mi|51|chain|km}}
|-
|[[Bristol Harbour|Floating Harbour]]
|{{convert|3|chain|m}}
|{{convert|118|mi|16|chain|km}} – {{convert|118|mi|19|chain|km}}
|}

==== Line-side monitoring equipment ====
Line-side train monitoring equipment includes hot axle box detectors (HABD) and ''Wheelchex'' wheel impact load detectors (WILD), sited as follows.<ref name=":0" /><ref>{{Cite web |url = http://www.railwaycodes.org.uk/misc/habdwild.shtm |title = HABD and WILD equipment |website = railwaycodes.org.uk}}</ref>
{| class="wikitable"
|+Line-side monitoring equipment on the Great Western Main Line
!Name & Type
!Line
!Location (distance from Paddington)
|-
| rowspan="2" |Maidenhead HABD
|Up Relief
|{{convert|24|mi|03|chain|km}}
|-
|Up Main
|{{convert|24|mi|10|chain|km}}
|-
|Waltham WILD
|Up Relief, Down Relief, Up Main, Down Main
|{{convert|26|mi|21|chain|km}}
|-
|Twyford HABD
|Down Relief, Down Main
|{{convert|32|mi|02|chain|km}}
|-
|Basildon HABD
|Up Relief, Down Relief, Up Main
(Down Main disconnected December 2016)
|{{convert|43|mi|42|chain|km}}
|-
|Cholsey WILD
|Up Relief, Down Relief, Up Main, Down Main
|{{convert|49|mi|05|chain|km}}
|-
|Wantage Road HABD
|Up Main
|{{convert|59|mi|57|chain|km}}
|-
|Bourton HABD
|Down Main
|{{convert|72|mi|20|chain|km}}
|-
|Studley HABD
|Up Main
|{{convert|81|mi|40|chain|km}}
|-
|Twerton HABD 
|Down Main
|{{convert|108|mi|60|chain|km}}
|}

==Recent developments==
{{Main|21st-century modernisation of the Great Western Main Line }}
From 2011, the GWML underwent a £5{{nbsp}}billion modernisation by Network Rail.{{sfn|Network Rail|2011|p=8}}

Reading station saw a major redevelopment with new platforms, a new entrance, footbridge and lifts; the work was completed a year ahead of schedule<ref name=bbc_9July2012>{{cite news |title = Reading rail station revamp 'a year ahead of schedule' |work = BBC News |date = 9 July 2012 |url = https://www.bbc.com/news/uk-england-berkshire-18769442 |access-date = 11 December 2015 |archive-date = 16 July 2021|archive-url = https://web.archive.org/web/20210716084222/https://www.bbc.com/news/uk-england-berkshire-18769442 |url-status = live |language = en-GB}}</ref> in July 2014.<ref>{{cite web |title = £425M transformation planned at Reading |url = http://www.railnews.co.uk/news/general/2008/09/10-reading-station-boost.htmlr|work = railnews.co.uk |access-date = 30 October 2011 |archive-date = 16 July 2021 |archive-url = https://web.archive.org/web/20210716084206/https://www.railnews.co.uk/news/general/2008/09/10-reading-station-boost.html |url-status = live |language = en-GB}}</ref><ref>{{cite web |url = https://www.bbc.co.uk/news/uk-england-berkshire-28334188 |title = Queen opens revamped Reading station |archive-url = https://web.archive.org/web/20210716084204/https://www.bbc.co.uk/news/uk-england-berkshire-28334188 |archive-date = 16 July 2021 |work = BBC News |date = 17 July 2014 |language = en-GB}}</ref>

Signalling Solutions resignalled the {{convert|12|mi|km}} from Paddington to {{rws|West Drayton}}, including the Airport branch, as part of the [[Elizabeth line]].<ref name="Rail671">{{cite magazine |magazine = [[Rail Magazine]] |issue = 671 |page = 17 |title = GWML signalling contract signed |date = 1–14 June 2011 |editor-first = Nigel |editor-last = Harris}}</ref>

===Electrification===
The eastern section from Paddington to Hayes & Harlington was electrified in 1998.{{Citation needed|date=March 2023}} 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 as far as Bristol Temple Meads.<ref>{{Cite web |date = 1 March 2011 |title = Great Western electrification and IEP to go ahead |url = https://www.railnews.co.uk/news/general/2011/03/01-great-western-electrification-and-iep.html |access-date = 1 July 2020 |website = railnews.co.uk |archive-date = 16 July 2021 |archive-url = https://web.archive.org/web/20210716084207/https://www.railnews.co.uk/news/general/2011/03/01-great-western-electrification-and-iep.html |url-status = live |language = en-GB}}</ref>{{sfn|Network Rail|2011|p=9}}<ref>{{cite web |last = Network Rail |date = June 2011 |title = Modernising the Great Western |url = http://www.networkrail.co.uk/uploadedFiles/networkrailcouk/Contents/Improvements/The_Great_Western/WesternVision.pdf |url-status = dead |archive-url = https://web.archive.org/web/20130413065743/http://www.networkrail.co.uk/uploadedFiles/networkrailcouk/Contents/Improvements/The_Great_Western/WesternVision.pdf |archive-date = 13 April 2013 |access-date = 24 August 2016 |language = en-GB}}</ref>

Following delays to the work and a large increase in costs,<ref>{{Cite web |date = 21 October 2015 |title = Cost of Great Western mainline electrification project triples to £2.8bn |url = https://www.theguardian.com/uk-news/2015/oct/21/cost-to-electrify-great-western-mainline-triples-to-28bn-risking-other-schemes |url-status = live |archive-url = https://web.archive.org/web/20210716084235/https://www.theguardian.com/uk-news/2015/oct/21/cost-to-electrify-great-western-mainline-triples-to-28bn-risking-other-schemes |archive-date = 16 July 2021 |access-date = 26 December 2016 |website = [[TheGuardian.com]] |language = en-GB}}</ref> the Conservative government announced in July 2017 that, for the time being, electrification would only be completed as far as Thingley Junction, {{convert|2|mi|km}} west of Chippenham.<ref>{{Cite news |last = Topham |first = Gwyn |date = 20 July 2017 |title = Grayling sparks fury by scrapping rail electrification plans |language = en-GB |work = The Guardian |url = https://www.theguardian.com/uk-news/2017/jul/20/grayling-sparks-fury-by-scrapping-rail-electrification-plans |url-status = live |access-date = 23 December 2017 |archive-url = https://web.archive.org/web/20210716084149/https://www.theguardian.com/uk-news/2017/jul/20/grayling-sparks-fury-by-scrapping-rail-electrification-plans |archive-date = 16 July 2021 |issn = 0261-3077}}</ref><ref>{{Cite web |date = 8 November 2016 |title = Great Western electrification projects deferred |url = https://www.railwaygazette.com/infrastructure/great-western-electrification-projects-deferred/43474.article |url-status = live |archive-url = https://web.archive.org/web/20210716084147/https://www.railwaygazette.com/infrastructure/great-western-electrification-projects-deferred/43474.article |archive-date = 16 July 2021 |access-date = 1 July 2020 |work = Railway Gazette International |language = en}}</ref> Electrification as far as [[Didcot Parkway railway station|Didcot Parkway]] was completed in December 2017,<ref>{{Cite web |date = 2 January 2018 |title = GWR Electrostar fleet enters service after electrification completed |url = http://www.railtechnologymagazine.com/Rail-News/gwr-electrostar-fleet-enters-service-after-electrification-completed |url-status = live |archive-url = https://web.archive.org/web/20180517214212/http://www.railtechnologymagazine.com/Rail-News/gwr-electrostar-fleet-enters-service-after-electrification-completed |archive-date = 17 May 2018 |access-date = 29 February 2024 |work = Railway Technology Magazine}}</ref> and to Thingley Junction in December 2019.{{Citation needed|date = July 2020}}

Electrification of associated lines, including [[Bristol Parkway railway station|Bristol Parkway]] to Temple Meads and Didcot to Oxford, was also postponed indefinitely; electrification of the route between London and Cardiff was completed in 2019.<ref>{{Cite web |date = 30 January 2020 |title = Major projects update: January |url = https://www.networkrail.co.uk/stories/major-projects-update-january |url-status = dead |archive-url = https://web.archive.org/web/20200131104248/https://www.networkrail.co.uk/stories/major-projects-update-january |archive-date = 31 January 2020 |access-date = 28 January 2023 |publisher = Network Rail |language = en-GB}}</ref> The government argued that bi-mode trains would fill in the gaps pending completion of electrification, although the [[British Rail Class 800|Class 800]] trains are slower in diesel mode than under electric power.

===Other proposals===
{{Update section|date=March 2023}}

Network Rail plans to install [[European Rail Traffic Management System]] (ERTMS) in-cab signalling on the Great Western line;<ref name="GvtRailElectricationPaper">{{cite web |url = http://www.dft.gov.uk/pgr/rail/pi/rail-electrification.pdf |title = DfT Rail Electrification paper |publisher = Department for Transport |access-date = 16 September 2013 |url-status = dead |archive-url = https://web.archive.org/web/20090805225151/http://www.dft.gov.uk/pgr/rail/pi/rail-electrification.pdf |archive-date = 5 August 2009 |language = en-GB}}</ref>{{sfn|Network Rail|2011|p=11}} this is a pre-requisite for the [[Intercity Express Programme|Super Express]] trains to run at 140{{nbsp}}mph (225{{nbsp}}km/h).<ref>See [[Hitachi Super Express]] article</ref> Some of this resignalling work was undertaken during the electrification work.<ref name="GvtRailElectricationPaper"/> Furthermore, Network Rail has envisaged the deployment of ERTMS to function as the replacement for the aging ATP system.<ref>{{cite web |url = http://www.dft.gov.uk/pgr/rail/pi/iep/iepinvitationtotender/infrastructureinterface.pdf |title = Network Rail Train Infrastructure Interface Specification |publisher = Department for Transport |access-date = 16 September 2013 |url-status = dead |archive-url = https://web.archive.org/web/20091122073905/http://www.dft.gov.uk/pgr/rail/pi/iep/iepinvitationtotender/infrastructureinterface.pdf |archive-date = 22 November 2009 |language = en-GB}}</ref>

Further capacity improvements are also scheduled at Swindon, adding to recent changes and the new Platform 4.{{citation needed|date=April 2024}}

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 the 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.{{citation needed|date=April 2024}}

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.<ref name="GvtRailElectricationPaper" /> Plans under consideration in 2014 included new tunnels between Heathrow and [[Langley, Berkshire|Langley]].<ref>{{cite news |title = Heathrow rail link plan unveiled by Network Rail |url = https://www.bbc.com/news/uk-england-26064200 |access-date = 11 April 2015 |work = BBC News |date = 6 February 2014 |archive-date = 16 July 2021 |archive-url = https://web.archive.org/web/20210716084240/https://www.bbc.com/news/uk-england-26064200 |url-status = live |language = en-GB}}</ref>

===Calls for station reopenings===
There are calls for the reintroduction of [[Corsham railway station|Corsham station]] due to recent growth of the town.<ref>{{cite news |last1 = Hicks |first1 = Amber |title = Corsham Station campaigners meet Department for Transport officials |url = http://www.wiltshiretimes.co.uk/news/latestheadlines/11568345.Corsham_Station_campaigners_meet_Department_for_Transport_officials/ |access-date = 11 April 2015 |work = Wiltshire Times |publisher = Newsquest (Oxfordshire and Wiltshire) |date = 30 October 2014 |archive-date = 17 April 2015 |archive-url = https://web.archive.org/web/20150417034244/http://www.wiltshiretimes.co.uk/news/latestheadlines/11568345.Corsham_Station_campaigners_meet_Department_for_Transport_officials/ |url-status = live |language = en-GB}}</ref> The [[Corsham railway station|original station]] was closed to passengers in 1965.

A local group is campaigning for the reopening of [[Saltford railway station|Saltford station]] between Bath and Bristol, to coincide with electrification.<ref>{{cite news |title = Rail-ly good news over station plan for Saltford |url = http://www.bathchronicle.co.uk/Rail-ly-good-news-station-plan/story-25616274-detail/story.html |access-date = 11 April 2015 |work = Bath Chronicle |publisher = Local World |date = 13 December 2014 |archive-url = https://web.archive.org/web/20150923192602/http://www.bathchronicle.co.uk/Rail-ly-good-news-station-plan/story-25616274-detail/story.html |archive-date = 23 September 2015 |url-status = dead |language = en-GB}}</ref>

There have also been calls to reopen the former [[Wantage Road railway station|Wantage Road station]].<ref>{{Cite news |url = https://www.bbc.co.uk/news/uk-england-29430204 |title = MPS call for direct rail service between Oxford and Bristol |work = BBC News |date = 30 September 2014 |access-date = 21 June 2018 |archive-date = 16 July 2021 |archive-url = https://web.archive.org/web/20210716084151/https://www.bbc.co.uk/news/uk-england-29430204 |url-status = live |language = en-GB}}</ref> [[Oxfordshire County Council]] included a proposal for a new station to serve Wantage and Grove in their 2015–2031 local transport plan.<ref>{{Cite web |url = https://www.oxfordshire.gov.uk/cms/sites/default/files/folders/documents/roadsandtransport/transportpoliciesandplans/localtransportplan/ConnectingOxfordshirevol1policyandoverallstrategy.pdf |title = Connecting Oxfordshire: Local Transport Plan 2015–2031 |access-date = 26 August 2015 |archive-date = 16 July 2021 |archive-url = https://web.archive.org/web/20210716084155/https://www2.oxfordshire.gov.uk/cms/sites/default/files/folders/documents/roadsandtransport/transportpoliciesandplans/localtransportplan/ConnectingOxfordshirevol1policyandoverallstrategy.pdf |url-status = live |language = en-GB}}</ref>

==Major incidents==
* [[Slough rail accident]] – 16 June 1900: An express train from Paddington to {{rws|Falmouth Docks}} ran through two sets of signals at danger and collided with a local train heading for [[Windsor & Eton Central railway station|Windsor]]. Five passengers were killed and 35 seriously injured.<ref name=Times21>{{cite news |url = https://www.newspapers.com/clip/32238736/the_times/ |title = The Railway Accident at Slough |newspaper = The Times |location = London, UK |date = 21 June 1900 |page = 11 |via = Newspapers.com}} {{open access}}</ref>
* [[Ealing rail crash]] – 19 December 1973: A train from Paddington to Oxford derailed after a loose battery box cover on the [[British Rail Class 52|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.<ref>{{cite web |url = https://www.railwaysarchive.co.uk/docsummary.php?docID=273 |title = Report on the Derailment that occurred on 19th December 1973 near West Ealing in the Western Region British Railways |first = I. K. A. |last = McNaughton |via = railwaysarchive.co.uk |date = 3 September 1974 |publisher = Department of the Environment}}</ref>
* [[Southall rail crash]] – 19 September 1997: An InterCity 125 service from Swansea to Paddington, operated by [[First Great Western|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 [[Automatic Warning System|automatic warning system]] (AWS) was faulty, and the driver had been distracted (he had bent down to pack his bag). Great Western Trains was fined £1.5{{nbsp}}million for violations of health and safety law in connection with the accident.<ref>{{cite web |url = http://www.railwaysarchive.co.uk/documents/HSE_Southall1997.pdf |title = The Southall Rail Accident Inquiry Report |first = John |last = Uff |author-link = John Uff |publisher = HSE Books |access-date = 7 November 2011 |language = en-GB}}</ref><ref>{{cite web |url = http://news.bbc.co.uk/2/hi/uk_news/405020.stm |title = Record fine after Southall crash |work = BBC News |date = 27 July 1999 |language = en-GB}}</ref>
* [[Ladbroke Grove rail crash]] – 5 October 1999: A [[Thames Trains]] service from Paddington to {{rws|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 {{rws|Cheltenham Spa}} to Paddington at a closing speed of approximately {{cvt|130|mph|kph}}. 31{{nbsp}}people died, including both drivers, with more than 520{{nbsp}}people injured. Thames Trains was fined £2{{nbsp}}million for violations of health and safety law.<ref>{{cite web |url = https://www.theguardian.com/traincrash/Story/0,,1186298,00.html |title = Thames Trains fined £2m for Paddington crash |work = The Guardian |date = 5 April 2004 |access-date = 17 December 2016 |archive-date = 16 July 2021|archive-url = https://web.archive.org/web/20210716084227/https://www.theguardian.com/uk/2004/apr/05/transport.ladbrokegrove |url-status = live |language = en-GB}}</ref> [[Railtrack]] pleaded guilty to charges under the [[Health and Safety at Work etc. Act 1974|Health and Safety at Work Act 1974]] in relation to the accident. It was subsequently fined £4{{nbsp}}million and was also ordered to pay £225,000 in costs.<ref>{{cite news |url = http://news.bbc.co.uk/1/hi/uk/6510077.stm |title = Paddington crash prompts £4m fine |work = BBC News |date = 30 March 2007 |access-date = 30 October 2011 |archive-date = 16 July 2021 |archive-url = https://web.archive.org/web/20210716084221/https://secure-uk.imrworldwide.com/v51.js |url-status = live |language = en-GB}}</ref>

==Rolling stock==
{{unreferenced section|date=July 2020}}

===Commuter trains===

{| class="wikitable"
|- style="background:#f9f9f9;"
! rowspan="2" |Class
! rowspan="2" |Image
! rowspan="2" |Type
! colspan="2" |Top speed
! rowspan="2" |Cars per set
! rowspan="2" |Number
! rowspan="2" |Operator
! rowspan="2" |Routes
! rowspan="2" |Built
|- style="background:#f9f9f9;"
!mph
!km/h
|-
| rowspan="2" | {{brc|158|n}}
| rowspan="2" | [[File:Bathpool - GWR 158763+158747 Cardiff service.JPG|150x150px]]
| rowspan="5" | [[Diesel Multiple Unit]]
| rowspan="5" | 90
| rowspan="5" | 145
| 2
| 22
|rowspan="2"| [[Great Western Railway (train operating company)|Great Western Railway]]
|rowspan="2"| 
* Cardiff Central – Portsmouth Harbour
* Cardiff Central/Bristol Temple Meads – Exeter St Davids
* Bristol Temple Meads – Weymouth
|rowspan="2"| 1989–92
|-
| 3
| 19
|-
| rowspan="2" | {{brc|165|n}}
| rowspan="2" | [[File:Oxford - GWR 165116 leaving for Reading.JPG|150px]]
|2
|20
| rowspan="2" | [[Great Western Railway (train operating company)|Great Western Railway]]
| rowspan="3" |
* Reading – Redhill or Gatwick Airport
* Reading – Basingstoke
* Reading or Didcot Parkway – Oxford or Banbury
* Twyford – Henley-on-Thames
* Maidenhead – Marlow
* Slough – Windsor & Eton Central
* West Ealing – Greenford
* Bristol Temple Meads – Avonmouth or Severn Beach
* Great Malvern – Bristol Temple Meads – Southampton Central or Weymouth
* Swindon – Gloucester or Weymouth
* Cardiff Central – Portsmouth Harbour

| rowspan="2" | 1990–92
|-
|3
|16
|-
| {{brc|166|n}}
| [[File:Caerdydd Canolog - GWR 166219.JPG|150x150px]]
| 3
| 21
| [[Great Western Railway (train operating company)|Great Western Railway]]
| 1992–93
|-
| {{brc|345|n}}
| [[File:Ealing Broadway - TfL 345015 Paddington service.JPG|150px]]
| rowspan="2" | [[Electric Multiple Unit]]
| 90
| 145
| 9
| 70
| [[Elizabeth line]]
| London Paddington to Heathrow Terminal 4, Heathrow Terminal 5 and Reading
| 2015–19
|-
| {{brc|387|n}}
| [[File:Reading - GWR 387132+387143 Didcot service.JPG|150x150px]]
| 110
| 177
| 4
| 36
| [[Great Western Railway (train operating company)|Great Western Railway]]
| London Paddington to Didcot Parkway<br>
London Paddington and Reading to Newbury
| 2016–17
|-
|}

===High speed trains===
{| class="wikitable"
|- style="background:#f9f9f9;"
! rowspan="2" |Class
! rowspan="2" |Image
! rowspan="2" |Type
! colspan="2" |Top speed
! rowspan="2" |Cars per set
! rowspan="2" |Number
! rowspan="2" |Operator
! rowspan="2" |Routes
! rowspan="2" |Built
|- style="background:#f9f9f9;"
!mph
!km/h
|-
|{{brc|220}}
|[[File:Reading railway station MMB 50 220013.jpg|150x150px]]
|rowspan="2"|[[Diesel electric multiple unit|DEMU]]
|rowspan="2"| 125
|rowspan="2"| 201
|rowspan="2"| 4 or 5
| 34
|rowspan="2"| [[CrossCountry]]
|rowspan="2"|
* Bristol Temple Meads — [[Exeter St Davids railway station|Exeter]], [[Paignton railway station|Paignton]], [[Plymouth railway station|Plymouth]] and [[Penzance railway station|Penzance]]
* Bristol Temple Meads — [[Birmingham New Street railway station|Birmingham New Street]], [[Manchester Piccadilly railway station|Manchester]], [[York railway station|York]], [[Newcastle railway station|Newcastle]], [[Edinburgh Waverley railway station|Edinburgh]], [[Dundee railway station|Dundee]] and [[Aberdeen railway station|Aberdeen]]
* [[Reading railway station|Reading]] — [[Oxford railway station|Oxford]], [[Birmingham New Street railway station|Birmingham New Street]], [[Southampton Central railway station|Southampton Central]] and [[Bournemouth railway station|Bournemouth]]
|rowspan="2"| {{nowrap|2000-01}}
|-
|{{brc|221}}
| [[File:Bath Spa - CrossCountry 221132 Edinburgh service.JPG|150x150px]]
| 22
|-
|rowspan="2"|{{brc|800}}
|rowspan="2"|[[File:Norton Fitzwarren - GWR 800003 Exeter to London.JPG|150x150px]]
| rowspan="4" |[[Bi-Mode Multiple Unit]]
| rowspan="4" |140
| rowspan="4" |225
|5
|36
| rowspan="4" | [[Great Western Railway (train operating company)|Great Western Railway]]
|rowspan="2"|London Paddington to:{{Unbulleted list| – Oxford, Bedwyn, Worcester Shrub Hill, Great Malvern, Hereford| – Cardiff Central, Swansea, Carmarthen| – Bristol Temple Meads, Weston-super-Mare| – Cheltenham Spa, Taunton, Paignton}}
|rowspan="2"|2014-18
|-
|9
|21
|-
|rowspan=2|{{brc|802}}
|rowspan=2|[[File:Bathpool - GWR 802110 London service.JPG|150x150px]]
|5
|22
|rowspan="2"| London Paddington to: {{Unbulleted list| – Exeter St Davids, Plymouth, Penzance| – Oxford, Bedwyn, Worcester Shrub Hill, Great Malvern, Hereford||}}
|rowspan="2"|2017-20
|-
|9
|14
|-
|}

===Sleeper trains===

{| class="wikitable"
|- style="background:#f9f9f9;"
! rowspan="2" |Class
! rowspan="2" |Image
! rowspan="2" |Type
! colspan="2" |Top speed
! rowspan="2" |Number
! rowspan="2" |Operator
! rowspan="2" |Routes
! rowspan="2" |Built
|- style="background:#f9f9f9;"
!mph
!km/h
|-
|{{brc|57}}
|[[File:St Philip's Marsh - GWR 57603.JPG|150px]]
|[[Diesel locomotive]]
|95
|152
|4
|rowspan="2"|[[Great Western Railway (train operating company)|Great Western Railway]] 
|rowspan="2"| {{Stn|London Paddington}} to {{Stnlnk|Penzance}} (The ''[[Night Riviera]]'')
|1998-2004
|-
|[[Sleeper Either Class|Mark 3]]
|[[File:Long Rock Sidings - GWR Mk3 RFB 10219.JPG|150px]]
|[[Passenger car (rail)|Passenger coach]]
|125
|200
|18
|1975-88
|-
|}

==Notes==
The reference for the route map diagram is:-
{{Jowett-Atlas|pages=113, 115a, 116, 118b, 118d, 120, 124–25}}

==See also==
* [[East Coast Main Line]]
* [[West Coast Main Line]]
* [[Midland Main Line]]
* [[Highland Main Line]]

==References==
===Citations===
{{Reflist}}

===Sources===
* {{cite book |title = BR Main Line Gradient Profiles: The Age of Steam |date = January 2003 |orig-year = 1966 |publisher = [[Ian Allan Publishing|Ian Allan]] |location = Hersham, UK |isbn=0-7110-0875-2 |id = 0301/A |ref = {{SfnRef|Gradient Profiles|2003}} }}
* {{citation |first = Andrew |last = Foster |date = June 2010 |title = A Review of the Intercity Express Programme |url = http://assets.dft.gov.uk/publications/review-of-the-intercity-express-programme-by-sir-andrew-foster/report.pdf |archive-url = https://web.archive.org/web/20111005174254/http://assets.dft.gov.uk/publications/review-of-the-intercity-express-programme-by-sir-andrew-foster/report.pdf |url-status = dead |archive-date = 5 October 2011 |language = en-GB }}
* {{citation |first = Andrew |last = Foster |date = June 2010a |title = A Review of the Intercity Express Programme (Annex) |url = http://assets.dft.gov.uk/publications/review-of-the-intercity-express-programme-by-sir-andrew-foster/annex.pdf |archive-url = http://webarchive.nationalarchives.gov.uk/20121107103953/http://assets.dft.gov.uk/publications/review-of-the-intercity-express-programme-by-sir-andrew-foster/annex.pdf |archive-date = 7 November 2012 |language = en-GB }}
* {{cite book |last = MacDermot |first = E.T. |title = History of the Great Western Railway, vol. I: 1833-1863 |year = 1927 |publisher = [[Great Western Railway]] |location = Paddington, UK }}
* {{cite web |url = https://content.historicengland.org.uk/images-books/publications/gwml-gazetteer/gwml-gazetteer.pdf/ |title = Great Western Main Line Route Structures Gazetteer – Prepared for Network Rail |date = April 2012 |publisher = Alan Baxter & Associates LLP |first1 = Joanna |last1 = Sanderson |first2 = Richard |last2 = Pollard |first3 = Robert |last3 = Thorne |first4 = Robert |last4 = Hradsky |first5 = Robert |last5 = Bevan |first6 = Jason |last6 = Howell |first7 = Boris |last7 = Bogdanovich |first8 = Tim |last8 = Harrison |editor-first = Susannah |editor-last = Meade |editor-first2 = Patricia |editor-last2 = Craggs }}

==Further reading==
* {{cite book |title = Pre-grouping Atlas and Gazetteer |publisher = Ian Allan Limited |year = 1976 |location = Shepperton, UK |isbn = 0-7110-0320-3 }}
* {{cite book |last = MacDermot |first = E T |title = History of the Great Western Railway, volume II 1863-1921 |publisher = [[Great Western Railway]] |year = 1931 |location = London, UK}}

== External links ==
{{Commons category|Great Western Main Line}}
{{Attached KML|display=title,inline}}
* {{BRin1960|WRLD01|Paddington, Reading General, Didcot and Milton}}
* {{BRin1960|WRLD02|Reading, Main Line West and Bedwyn}}
{{Great Western Railway}}
{{Brunel}}
{{Main inter-regional railway lines in Great Britain}}
{{Railway lines in London}}
{{Railway lines in South East England}}
{{Railway lines in South West England}}
{{Transport in Buckinghamshire}}
{{Transport in Bristol}}
{{Crossrail navbox}}

[[Category:Great Western Main Line| ]]
[[Category:Rail transport in Berkshire]]
[[Category:Rail transport in Bristol]]
[[Category:Rail transport in Buckinghamshire]]
[[Category:Rail transport in Oxfordshire]]
[[Category:Rail transport in Wiltshire]]
[[Category:Railway operators in London]]
[[Category:Transport in the London Borough of Ealing]]
[[Category:Transport in the London Borough of Hammersmith and Fulham]]
[[Category:Transport in the London Borough of Hillingdon]]
[[Category:Transport in the Royal Borough of Kensington and Chelsea]]
[[Category:Transport in the City of Westminster]]
[[Category:Railway lines opened in 1840]]
[[Category:Railway lines in London]]
[[Category:Railway lines in South East England]]
[[Category:Railway lines in South West England]]
[[Category:Main inter-regional railway lines in Great Britain]]
[[Category:Standard gauge railways in England]]