Great Western Main Line

The Great Western Main Line is a main line railway in Great Britain, that runs westwards from London's Paddington station to the west of England and South Wales. The core Great Western Main Line runs from London Paddington to Temple Meads railway station in Bristol. A major branch of the Great Western, the South Wales Main Line, diverges from the core line west of Swindon and terminates in Swansea. The term "Great Western" is also used by Network Rail and other rail transport organisations in the UK rail industry to denote a wider group of routes, see Associated routes below.

The core London–Bristol Temple Meads line is the original route of the pre-1948 Great Western Railway which was subsequently taken over by the Western Region of British Railways and is now part of the Network Rail system.

The line is planned to be electrified by 2016. The South Wales Main Line, the Cherwell Valley Line and the Reading to Taunton Line as far as Newbury will also be electrified at later dates.

History
The line was built by the Great Western Railway and engineered by Isambard Kingdom Brunel as a dual track line using a wider broad gauge and was opened in stages between 1838 and 1840. 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 trains to also operate on the route in stages between 1854 and 1875. Dual gauge was introduced as follows: London to Reading (1 October 1861), Reading to Didcot (22 December 1856), Didcot to Swindon (February 1872), Swindon to Thingley Junction, Chippenham (June 1874), Thingley Junction to Bathampton (16 March 1875), Bathampton to Bristol (June 1874), Bristol station area (29 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.

The original dual tracks were widened to four track in various places between 1877 and 1899. Paddington to Southall (1 October 1877), Southall to West Drayton (25 November 1878), West Drayton to Slough (1 June 1879), Slough to east side of Maidenhead Bridge (8 September 1884), Maidenhead Bridge to Reading (4 June 1893), Reading station (1899), Reading to Pangbourne (30 July 1893), Pangbourne to Cholsey and Moulsford (?), Cholsey and Moulsford to Didcot (27 December 1892), Various short sections between Didcot and Swindon, and at Bristol.

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.

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 in 1948.

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

In 1977 the Parliamentary Select Committee on Nationalised Industries recommmended considering electrification of more of Britain's rail network, and by 1979 BR presented a range of options that included electrifying the GW Main Line from Paddington to Swansea by 2000. 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 have been raised so that 86% of the line can be used at 90 mph, however the time allowed between stations for trains running on the relief lines has been reduced in the December 2008 timetable to improve timekeeping.

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; 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 as managed by Network Rail as part of the Great Western Main Line (Route 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 First Great Western (FGW). The stations served by express trains between London Paddington and Bristol Temple Meads are: Slough, Reading, Didcot Parkway, Swindon, Chippenham, Bath Spa and Keynsham. Not all trains call at all of these stations, especially Slough, Didcot and Keynsham.

Fast trains from Paddington to London Heathrow Airport are operated by BAA as the Heathrow Express. Local services on this route are jointly operated by FGW 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 West Trains operate a limited number of trains between Bath and Bristol.

First Great Western also operate a train between London Paddington – Cardiff Central (South Wales) every 30 minutes, with hourly extensions to Swansea. At Swansea/Cardiff there is a connecting Arriva Trains Wales boat train to/from Fishguard Harbour railway station 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. Daytime and nocturnal journeys are offered in both directions daily (including Sundays). Additionally, 2–3 First Great Western trains continue to Pembroke Dock on weekends during the Summer season to connect with ferry services to Ireland.

Infrastructure
Between London and Didcot there are four tracks, grouped by speed with the "relief" lines on the north side of the "main" lines. Most smaller stations only have platforms in use on the relief lines. Between Didcot and Royal Wootton Bassett there are a series of passing loops lines to allow fast trains to overtake slower ones. This section is also 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.

The line is currently not electrified except for a short 12 miles section of electrified 25 kV AC overhead wires between Paddington and Airport Junction (the junction with the line to London Heathrow Airport near Hayes).

The line speed is 125 mph. The relief lines from Paddington to Didcot are currently limited to 90 mph as far as Reading, and then 100 mph to Didcot. Lower restrictions apply at various locations. It is one of only two Network Rail-owned lines to be equipped with the Automatic Train Protection (ATP) system, the other being the Chiltern Main Line.

Planned developments
The Great Western is currently undergoing a £5 billion modernisation by Network Rail.

Reading railway station is undergoing a major redevelopment with new platforms, a new entrance, footbridge and lifts.

Swansea railway station is to undergo renovation which will include an enlarged concourse, a new entrance, a new partition wall between concourse and platforms together with a new cafe and more shops.

A major renewal programme is underway from bases at Reading and Taunton.

Electrification west of Airport Junction
As part of Crossrail the Great Western was already planned to be electrified from Airport Junction to Maidenhead but, following a number of announcements and delays the government announced in March 2011 that the line would be electrified between London and Cardiff together with the section linking Bristol Parkway and Bristol Temple Meads.

Other proposals
Network Rail plans to install European Rail Traffic Management System (ERTMS) in-cab signalling on the Great Western line: this is a pre-requisite for the new Super Express trains to run at 140 mph (225 km/h). Some or all of the resignalling work will be done during the electrification work.

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

Crossrail services are planned to terminate at Maidenhead. However, with electrification of the Great Western now being extended westwards beyond Maidenhead, the Department of Transport is considering extending Crossrail to terminate at Reading from the outset. 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.

By 2016, there are plans for a direct rail link from Swindon to London Heathrow Airport. There are also calls for the reintroduction of a station at Corsham due to recent growth of the town. The original station was closed to passengers in 1965.

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 down (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. A local group is campaigning for the reopening of Saltford station between Bath and Bristol, to coincide with electrification.

Access to Heathrow Airport from the west remains an aspiration and there is a proposed future link to Heathrow Airport directly from Reading under the Heathrow Airtrack scheme which would use a route south of the Great Western main line. Plans for electrification of the line will make it easier to access Heathrow from Reading given that lack of electrification between Reading station and Heathrow Airport Junction near West Drayton station was a limiting factor.

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

Signalling Solutions is to resignal the 12 miles from Paddington to West Drayton, including the Airport branch, as part of the Crossrail project.

Slough rail accident
The Slough rail accident in June 1900 occurred after 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 were seriously injured.

Ealing rail crash
The Ealing rail crash occurred on 19 December 1973 when a train from Paddington to Oxford derailed: ten passengers were killed and 94 injured. The cause of the accident was a loose battery box cover on the BR Class 52 "Western" locomotive, that struck line side equipment, causing a set of points to move under the train.

Southall rail crash
The Southall rail crash in 1997 resulted in seven deaths and 139 injuries and 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
The Ladbroke Grove rail crash in 1999 resulted in 31 deaths (including the drivers of both trains) and more than 520 injured. It remains the worst rail accident on the Great Western Main Line. Thames Trains was fined a record £2 million for violations of health and safety law in connection with this accident. 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.