Great Western Main Line
Maidenhead Railway Bridge carrying the line over the River Thames.
Overview
Status	Operational
Owner	Network Rail
Locale	Greater London South East England South West England
Termini	London Paddington Bristol Temple Meads
Stations	25
Service
Type	Commuter rail, Higher-speed rail[1]
System	National Rail
Operator(s)	Great Western Railway Elizabeth line Heathrow Express Chiltern Railways CrossCountry
Depot(s)	North Pole Reading St Philip's Marsh depot
Rolling stock	Class 158 Class 159 Class 165 Class 166 Class 220 Class 221 Class 345 Class 387 Class 800 Class 802
History
Opened	30 June 1841 (complete line)
Technical
Line length	118 miles 19 chains (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	25 kV 50 hz AC OLE (London to Chippenham)
Operating speed	125 mph (201 km/h) maximum
Signalling	AWS, TPWS, ATP
Route map (Click to expand – Interactive map)

Great Western Main Line
miles Circle and Hammersmith & City lines via Liverpool Street Elizabeth line to Abbey Wood and Stratford 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 5¾ 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 11⅓ Hayes & Harlington Airport Junction to Heathrow Airport stations 14⅓ West Drayton River Colne Greater London boundary 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 Terminals 2 & 3 and Terminal 5 (proposed) 16¼ Langley 18½ Slough Slough–Windsor & Eton line 21⅓ Burnham 22½ Taplow Jubilee River Maidenhead Railway Bridge over River Thames 24¼ 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 38¾ Tilehurst Purley Cutting 41½ Pangbourne Gatehampton Railway Bridge over River Thames 44¾ Goring & Streatley Moulsford Railway Bridge over River Thames Moulsford 48½ Cholsey Cholsey & Wallingford Railway (bank holidays and weekends only) Didcot, Newbury and Southampton Railway 53⅓ Didcot Parkway Didcot Railway Centre Cherwell Valley line to Oxford, Birmingham and the Cotswold Line Didcot power stations Milton Park estate 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 & South Western Junction Railway M4 motorway Wootton Bassett Junction South Wales Main Line Dauntsey Malmesbury branch line Christian Malford Halt Calne branch line 94⅓ 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 107⅓ Bath Spa 108⅓ Oldfield Park Somerset & Dorset Joint Railway 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 & North Somerset Railway St Philip's Marsh TMD Cross Country Route to Gloucester & Birmingham New Street to Mangotsfield to Ashton Gate Platform 116½ Bristol Temple Meads Bristol West Junction Temple Meads Goods Bristol–Exeter line

The Great Western Main Line (GWML) is a main line railway in England that runs westwards from London Paddington to Bristol Temple Meads. It connects to other main lines such as those from Reading to Penzance and Swindon to Swansea.^[2] Opened in 1841, it was the original route of the first Great Western Railway which was merged into the Western Region of British Railways in 1948. It is now a part of the national rail system managed by Network Rail with the majority of passenger services provided by the current Great Western Railway franchise.

The line is electrified between London Paddington and Royal Wootton Bassett. Work to complete electrification all the way to Bristol was begun in 2011, but in 2016 the UK government deferred electrification of the section through Bath from Royal Wootton Bassett to Bristol, with no date set for completion, because costs had tripled.

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.^[3]

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 bit wider than usual, or where tracks are ten feet apart instead of the usual six.

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 (June 1894), Cholsey and Moulsford to Didcot (December 1892); also short sections between Didcot and Swindon, and at Bristol.

Following the Slough rail accident of 1900, in which 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.^[4]

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. The companies 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.

The line speed was upgraded in the 1970s to support the introduction of the InterCity 125 high speed train (HST).^[5]

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.^[6] Under the 1979–90 Conservative governments that succeeded the 1976–79 Labour government, the proposal was not implemented.

In the mid 1990s, the line between London Paddington and Hayes & Harlington was electrified as part of the Heathrow Express project.^[7]

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 mph (140 km/h).^[8]

Partial electrification by 2019 allowed replacement of InterCity 125 and Class 180 sets by new Hitachi Super Express high speed trains – the Class 800s and Class 802s. It also allowed the introduction of Class 387 EMUs by GWR on shorter-distance services.^[9]

Route

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 Maidenhead Railway Bridge. Between Chippenham and Bath the line passes through Box Tunnel, and then follows the valley of the 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 the Wessex Main Line, although this involves a reversal at Bradford Junction; and from Reading to Bath via the Berks and Hants Line.

Services

Most services are provided by Great Western Railway (GWR). The stations served by trains between London Paddington and Bristol Temple Meads are Reading, Didcot Parkway, Swindon, Chippenham, and Bath Spa. Some trains between London and Bristol do not call at Didcot Parkway.

The Elizabeth line runs on the Great Western Main Line between London and Reading.

Fast trains from Paddington to London Heathrow Airport are operated by Heathrow Airport Holdings as the Heathrow Express.

CrossCountry operate trains between Reading and Oxford, using the Great Western Main Line as far as Didcot.

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.^[13] Daytime and nocturnal journeys are offered in both directions daily (including Sundays).

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.^[14]

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.^[15][16]

The line is electrified between Paddington and Langley Burrell (just east of Chippenham) using 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 125 mph (201 km/h).^[17] The relief lines from Paddington to Didcot are limited to 90 mph (140 km/h) as far as Reading, and then 100 mph (160 km/h) to Didcot. Lower restrictions apply at various locations.^[14] 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.^[18]

Recent developments

Since 2011, the Great Western has been undergoing a £5 billion modernisation by Network Rail.^[21]

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^[22] in July 2014.^[23][24]

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 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 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 mph (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.^[41] Railtrack 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.^[42]

Rolling stock

Commuter trains

Class	Image	Type	Top speed		Cars per set	Number	Operator	Routes	Built
			mph	km/h
Class 158		Diesel Multiple Unit	90	145	2	22	Great Western Railway	Cardiff Central – Portsmouth Harbour Cardiff Central/Bristol Temple Meads – Exeter St Davids Bristol Temple Meads – Weymouth	1989–92
					3	19
Class 165		Diesel Multiple Unit	90	145	2	20	Great Western Railway	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	1990-92
					3	16
Class 166		Diesel Multiple Unit	90	145	3	21	Great Western Railway		1992-93
Class 345		Electric Multiple Unit	90	145	9	70	Elizabeth line	London Paddington to Heathrow Terminal 4 and Reading	2015-19
Class 387		Electric Multiple Unit	110	177	4	36	Great Western Railway	London Paddington to Didcot Parkway London Paddington and Reading to Newbury	2016–17

High speed trains

Class	Image	Type	Top speed		Cars per set	Number	Operator	Routes	Built
			mph	km/h
Class 220		DEMU	125	201	4	34	CrossCountry	Bristol Temple Meads — Exeter, Paignton, Plymouth and Penzance Bristol Temple Meads — Birmingham New Street, Manchester, York, Newcastle, Edinburgh, Dundee and Aberdeen Reading — Oxford, Birmingham New Street, Southampton Central and Bournemouth	2000-01
Class 221			125	201	5	22
Class 387		Electric Multiple Unit	110	177	4	12	Heathrow Express	London Paddington to Heathrow Terminal 5	2016-17
Class 800		Bi-Mode Multiple Unit	140	225	5	36	Great Western Railway	London Paddington to: – Oxford, Bedwyn, Worcester Shrub Hill, Great Malvern, Hereford – Cardiff Central, Swansea, Carmarthen – Bristol Temple Meads, Weston-super-Mare – Cheltenham Spa, Taunton, Paignton	2014-18
					9	21
Class 802		Bi-Mode Multiple Unit	140	225	5	22	Great Western Railway	London Paddington to: – Exeter St Davids, Plymouth, Penzance – Oxford, Bedwyn, Worcester Shrub Hill, Great Malvern, Hereford	2017-20
					9	14

Sleeper trains

Class	Image	Type	Top speed		Number	Operator	Routes	Built
			mph	km/h
Class 57		Diesel locomotive	95	152	4	Great Western Railway	London Paddington to Penzance (The Night Riviera)	1998-2004
Mark 3		Passenger coach	125	200	18			1975-88

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.

See also

• East Coast Main Line
• West Coast Main Line
• Midland Main Line
• Highland Main Line

References

Further reading

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

• Paddington, Reading General, Didcot and Milton (British Railways in the 1960s Sectional Appendix Extract) (via The Internet Archive)
• Reading, Main Line West and Bedwyn (British Railways in the 1960s Sectional Appendix Extract) (via The Internet Archive)