The South Wales Main Line ( cy, Prif Linell De Cymru), originally known as the London, Bristol and South Wales Direct Railway or simply as the Bristol and South Wales Direct Railway, is a branch of the
Great Western Main Line
The Great Western Main Line (GWML) is a main line railway in England that runs westwards from London Paddington to . It connects to other main lines such as those from Reading to Penzance and Swindon to Swansea. Opened in 1841, it was the or ...
in Great Britain. It diverges from the core London-Bristol line at
Royal Wootton Bassett beyond
Swindon
Swindon () is a town and unitary authority with Borough status in the United Kingdom, borough status in Wiltshire, England. As of the 2021 Census, the population of Swindon was 201,669, making it the largest town in the county. The Swindon un ...
, first calling at
Bristol Parkway
Bristol Parkway, on the South Wales Main Line, is in the Stoke Gifford area in the northern suburbs of the Bristol conurbation. It is from London Paddington. The station was opened in 1972 by British Rail, and was the first in a new gener ...
, after which the line continues through the
Severn Tunnel into
South Wales
South Wales ( cy, De Cymru) is a loosely defined region of Wales bordered by England to the east and mid Wales to the north. Generally considered to include the historic counties of Glamorgan and Monmouthshire, south Wales extends westwards ...
.
Great Western Railway
The Great Western Railway (GWR) was a British railway company that linked London with the southwest, west and West Midlands of England and most of Wales. It was founded in 1833, received its enabling Act of Parliament on 31 August 1835 and ran ...
operates
Class 800 trains between London and
South Wales
South Wales ( cy, De Cymru) is a loosely defined region of Wales bordered by England to the east and mid Wales to the north. Generally considered to include the historic counties of Glamorgan and Monmouthshire, south Wales extends westwards ...
, and
Classes 253, 254 and 255 High Speed Trains on services between
Cardiff and
South West England.
CrossCountry
CrossCountry (legal name XC Trains Limited) is a train operating company in the United Kingdom owned by Arriva UK Trains, operating the Cross Country franchise.
The CrossCountry franchise was restructured by the Department for Transport (DfT) ...
provides services from Cardiff to
Nottingham via
Severn Tunnel Junction
, name_etymology =
, image = SevernFromCastleCB.JPG
, image_size = 288
, image_caption = The river seen from Shrewsbury Castle
, map = RiverSevernMap.jpg
, map_size = 288
, map_c ...
and thence the
Gloucester to Newport Line via
Gloucester and
Birmingham.
Transport for Wales operates services between South Wales, and North Wales and the Midlands on the line.
The line between Wootton Bassett and Cardiff Central is electrified using the 25 kV AC overhead system, as part of the larger electrification of the Great Western Main Line.
History
The original route of the
Great Western Railway
The Great Western Railway (GWR) was a British railway company that linked London with the southwest, west and West Midlands of England and most of Wales. It was founded in 1833, received its enabling Act of Parliament on 31 August 1835 and ran ...
(GWR) between London and South Wales, after the opening of
Brunel
Isambard Kingdom Brunel (; 9 April 1806 – 15 September 1859) was a British civil engineer who is considered "one of the most ingenious and prolific figures in engineering history," "one of the 19th-century engineering giants," and "one ...
's
Chepstow Railway Bridge in 1852, left the Bristol-bound
Great Western Main Line
The Great Western Main Line (GWML) is a main line railway in England that runs westwards from London Paddington to . It connects to other main lines such as those from Reading to Penzance and Swindon to Swansea. Opened in 1841, it was the or ...
at
Swindon
Swindon () is a town and unitary authority with Borough status in the United Kingdom, borough status in Wiltshire, England. As of the 2021 Census, the population of Swindon was 201,669, making it the largest town in the county. The Swindon un ...
, proceeding via
Stroud
Stroud is a market town and civil parish in Gloucestershire, England. It is the main town in Stroud District. The town's population was 13,500 in 2021.
Below the western escarpment of the Cotswold Hills, at the meeting point of the Five ...
,
Gloucester and
Chepstow before rejoining the present line at
Severn Tunnel Junction
, name_etymology =
, image = SevernFromCastleCB.JPG
, image_size = 288
, image_caption = The river seen from Shrewsbury Castle
, map = RiverSevernMap.jpg
, map_size = 288
, map_c ...
. This gave rise to the nickname 'Great Way Round'.
In 1886, the opening of the
Severn Tunnel brought the opportunity of a more direct route to
South Wales
South Wales ( cy, De Cymru) is a loosely defined region of Wales bordered by England to the east and mid Wales to the north. Generally considered to include the historic counties of Glamorgan and Monmouthshire, south Wales extends westwards ...
, and trains from Swindon to
Newport
Newport most commonly refers to:
*Newport, Wales
*Newport, Rhode Island, US
Newport or New Port may also refer to:
Places Asia
*Newport City, Metro Manila, a Philippine district in Pasay
Europe
Ireland
*Newport, County Mayo, a town on the ...
and beyond were routed via
Bath
Bath may refer to:
* Bathing, immersion in a fluid
** Bathtub, a large open container for water, in which a person may wash their body
** Public bathing, a public place where people bathe
* Thermae, ancient Roman public bathing facilities
Plac ...
,
Bristol and the tunnel.
The route used today was established in 1903 with the building of what is often known as the
Badminton Line. This involved the construction of about of new track, and tunnels at
Alderton and
Sodbury. The new line left the Bath line beyond Swindon at what is now
Royal Wootton Bassett, rejoining the earlier route north of Bristol near
Patchway. Not only did this provide a more direct route for traffic to and from South Wales, the gradients were easier for coal trains to negotiate, and it was thought that the line would be a boost to what was, at the time of building, the expanding port of
Fishguard. This was the GWR's connection with
trans-Atlantic ocean liner
An ocean liner is a passenger ship primarily used as a form of transportation across seas or oceans. Ocean liners may also carry cargo or mail, and may sometimes be used for other purposes (such as for pleasure cruises or as hospital ships).
Ca ...
departures.
Infrastructure

There are four tracks from
Severn Tunnel Junction
, name_etymology =
, image = SevernFromCastleCB.JPG
, image_size = 288
, image_caption = The river seen from Shrewsbury Castle
, map = RiverSevernMap.jpg
, map_size = 288
, map_c ...
through Newport to Cardiff Central, with two tracks on the remaining sections.
Multiple-aspect signals are controlled from several power
signal box
In signal processing, a signal is a function that conveys information about a phenomenon. Any quantity that can vary over space or time can be used as a signal to share messages between observers. The ''IEEE Transactions on Signal Processing'' ...
es including Swindon, Bristol and two in Cardiff. Over the August Bank Holiday weekend 2016, control of the signals between Westerleigh Junction and Pilning was switched over to the Thames Valley Signalling Centre. These signals now carry the prefix 'BL'.
The maximum line speed from Wootton Bassett Junction to Coalpit Heath is ; from Coalpit Heath to Newport; from Newport to east of Bridgend; from east of Bridgend to Swansea Loop North junction (with a small section of track through
Pyle station); and from Swansea Loop North Junction to Swansea.
Associated routes
A diversionary route exists if the
Severn Tunnel is closed. This takes trains from
Severn Tunnel Junction to Gloucester, from where they can rejoin the main line either via the
Golden Valley Line to Swindon, or take the
Cross-Country Route
Cross country or cross-country may refer to:
Places
* Cross Country, Baltimore, a neighborhood in northwest Baltimore, Maryland
* Cross County Parkway, an east–west parkway in Westchester County, NY
* Cross County Shopping Center, a mall in Yo ...
and reverse at
Bristol Parkway
Bristol Parkway, on the South Wales Main Line, is in the Stoke Gifford area in the northern suburbs of the Bristol conurbation. It is from London Paddington. The station was opened in 1972 by British Rail, and was the first in a new gener ...
.
If the line is closed between and , an alternative route exists along the
Vale of Glamorgan Line.
Half of peak High Speed Trains and most off peak trains continue from Cardiff Central to Swansea, with a few continuing to or in summer, .
The local service between Swansea and Cardiff is branded
Swanline
Swanline is the name of the local rail service from to , on the South Wales Main Line.
History
The Swanline service was launched in June 1994, following the construction of five new stations at , , , and on the existing South Wales Main Li ...
. The urban network within and surrounding Cardiff, including the
Maesteg Line, is referred to as
Valley Lines.
Plans
Traffic levels on the Great Western Main Line are rising faster than the national average, with continued increases predicted. The now defunct
Strategic Rail Authority
The Strategic Rail Authority (SRA) was a non-departmental public body in the United Kingdom set up under the Transport Act 2000 to provide strategic direction for Rail transport in the United Kingdom, the railway industry. Its motto was 'Brita ...
produced a Route Utilisation Strategy for the Great Western Main Line in 2005 to propose ways of meeting this demand.
Network Rail's 2007 Business Plan included the provision of extra platform capacity at ,
Newport
Newport most commonly refers to:
*Newport, Wales
*Newport, Rhode Island, US
Newport or New Port may also refer to:
Places Asia
*Newport City, Metro Manila, a Philippine district in Pasay
Europe
Ireland
*Newport, County Mayo, a town on the ...
and , also resignalling and line speed improvements in South Wales, most of which would be delivered in 2010–2014.
Reading railway station underwent a major redevelopment being reopened in July 2014 and there is a proposed future link to
Heathrow Airport
Heathrow Airport (), called ''London Airport'' until 1966 and now known as London Heathrow , is a major international airport in London, England. It is the largest of the six international airports in the London airport system (the others be ...
directly from Reading under the
Heathrow Airtrack scheme.
Electrification

The South Wales Main Line was one of the last of the major inter-city routes in Great Britain to remain un-electrified. The government announced in 2012 a scheme to electrify the South Wales Main Line as part of a wider scheme of electrification on the Great Western Main Line. The line from London to Cardiff was fully electrified by Christmas 2019.
The new
Hitachi Super Express trains planned for the Great Western inter-city services are predominantly
electric units instead of the planned diesel units. However, a proportion of the fleet are dual power source
electro-diesel
An electro-diesel locomotive (also referred to as a dual-mode or bi-mode locomotive) is a type of locomotive that can be powered either from an electricity supply (like an electric locomotive) or by using the onboard diesel engine (like a diese ...
bi-mode trains, which enabled services to operate before line electrification is complete. The bi-mode trains will allow inter-city services to continue to operate from London all the way to
Carmarthen in the future. The new Super Express trains will bring about an estimated 15% increased capacity during the morning peak hours. Electrification has cut journey times between Swansea and London by an estimated 20 minutes, although electrification will not extend west of Cardiff to Swansea, Carmarthen or Pembroke Dock, and services on the line to Brighton, Portsmouth Harbour and Taunton will continue to be operated by diesel trains, as the Bristol to Exeter Line and the
Wessex Main Line
The Wessex Main Line is the railway line from Bristol Temple Meads to Southampton Central. Diverging from this route is the Heart of Wessex Line from Westbury to Weymouth. The Wessex Main Line intersects the Reading to Taunton Line at and th ...
will not be electrified.
Communities served
;Towns and cities served by trains from London:
*
Reading
*
Didcot
*
Swindon
Swindon () is a town and unitary authority with Borough status in the United Kingdom, borough status in Wiltshire, England. As of the 2021 Census, the population of Swindon was 201,669, making it the largest town in the county. The Swindon un ...
*
Bristol
*
Newport
Newport most commonly refers to:
*Newport, Wales
*Newport, Rhode Island, US
Newport or New Port may also refer to:
Places Asia
*Newport City, Metro Manila, a Philippine district in Pasay
Europe
Ireland
*Newport, County Mayo, a town on the ...
*
Cardiff
*
Bridgend
*
Port Talbot
*
Neath
Neath (; cy, Castell-nedd) is a market town and Community (Wales), community situated in the Neath Port Talbot, Neath Port Talbot County Borough, Wales. The town had a population of 50,658 in 2011. The community of the parish of Neath had a po ...
*
Swansea
Swansea (; cy, Abertawe ) is a coastal city and the second-largest city of Wales. It forms a principal area, officially known as the City and County of Swansea ( cy, links=no, Dinas a Sir Abertawe).
The city is the twenty-fifth largest in ...
;Settlements served by local trains only:
*
Patchway
*
Pilning (
very limited service)
*
Magor Magor may refer to the following:
;Places
* Magor, Monmouthshire, a village in Wales, United Kingdom
* Magor with Undy, a community in Wales, United Kingdom
* Magor Farm, a Romano-British villa near Illogan in Cornwall
* Breton name for Magoar
* C ...
*
Rogiet
*
Llanharan
Llanharan is a village and community in the county borough of Rhondda Cynon Taf, Wales. As a community Llanharan takes in the neighbouring settlements of Bryncae, Brynna, Llanilid, Peterston-super-Montem and Ynysmaerdy. Llanharan thrived during ...
*
Pontyclun
*
Pencoed
Pencoed ( cy, Pen-coed) is a urbanised community and town in the county borough of Bridgend, Wales. It straddles the M4 motorway north east of Bridgend and is situated on the Ewenny River. At the 2011 census it had a population of around 9,166.
...
*
Pyle
*
Baglan
*
Briton Ferry
Briton Ferry ( cy, Llansawel) is a town and community in the county borough of Neath Port Talbot, Wales. The Welsh name may indicate that the church, ''llan'', is protected from the wind, ''awel''. Alternatively, ''Sawel'' may be a derivative ...
*
Skewen
*
Llansamlet
Llansamlet is a suburban district and community of Swansea, Wales, falling into the Llansamlet ward. The area is centred on the A48 road (named Samlet Road and Clase Road in the area) and the M4 motorway.
Like other places in Wales having a name ...
Accidents and incidents
*On 7 March 2015,
''Battle of Britain''-class locomotive 34067 ''Tangmere'' was hauling a charter train that
overran a signal at Wooton Bassett,
Wiltshire. The train's operator,
West Coast Railway Company was banned from running trains on the British railway network as a direct consequence of this incident.
See also
*
Transport in Wales
*
Transport in England
*
South Wales Railway
*
Great Western Main Line
The Great Western Main Line (GWML) is a main line railway in England that runs westwards from London Paddington to . It connects to other main lines such as those from Reading to Penzance and Swindon to Swansea. Opened in 1841, it was the or ...
References
*
External links
2007 Business Plan Network Rail, London
{{Transport in Bristol
Rail transport in Bridgend County Borough
Rail transport in Bristol
Rail transport in Cardiff
Rail transport in Neath Port Talbot
Rail transport in Newport, Wales
Rail transport in Rhondda Cynon Taf
Rail transport in Swansea
Rail transport in Wiltshire
Railway lines opened in 1903
Railway lines in South West England
Railway lines in Wales
Standard gauge railways in England
Standard gauge railways in Wales