South West Main Line
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The South West Main Line (SWML) is a 143-mile (230 km) major railway line between Waterloo station in central London and Weymouth on the south coast of England. A predominantly passenger line, it serves many commuter areas including south western suburbs of London and the conurbations based on
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and
Bournemouth Bournemouth ( ) is a coastal resort town in the Bournemouth, Christchurch and Poole unitary authority area, in the ceremonial county of Dorset, England. At the 2021 census, the built-up area had a population of 196,455, making it the largest ...
. It runs through the counties of
Surrey Surrey () is a Ceremonial counties of England, ceremonial county in South East England. It is bordered by Greater London to the northeast, Kent to the east, East Sussex, East and West Sussex to the south, and Hampshire and Berkshire to the wes ...
,
Hampshire Hampshire (, ; abbreviated to Hants.) is a Ceremonial counties of England, ceremonial county in South East England. It is bordered by Berkshire to the north, Surrey and West Sussex to the east, the Isle of Wight across the Solent to the south, ...
and
Dorset Dorset ( ; Archaism, archaically: Dorsetshire , ) is a Ceremonial counties of England, ceremonial county in South West England. It is bordered by Somerset to the north-west, Wiltshire to the north and the north-east, Hampshire to the east, t ...
. It forms the core of the network built by the
London and South Western Railway The London and South Western Railway (LSWR, sometimes written L&SWR) was a railway company in England from 1838 to 1922. Originating as the London and Southampton Railway, its network extended to Dorchester and Weymouth, to Salisbury, Exete ...
, today mostly operated by
South Western Railway South Western Railway Limited, trading as South Western Railway (SWR), is the British state-owned train operating company that took over the services of the South Western Railway (2017–2025), operator of the same name from FirstGroup and MTR ...
. Operating speeds on much of the line are relatively high, with large stretches cleared for up to running. The line has four tracks for most of the length between Waterloo and Worting Junction, south west of , from which point most of the line is
double track A double-track railway usually involves running one track in each direction, compared to a single-track railway where trains in both directions share the same track. Overview In the earliest days of railways in the United Kingdom, most li ...
. A couple of miles from the Waterloo terminus, the line runs briefly alongside the
Brighton Main Line The Brighton Main Line is a railway line in southern England linking London to Brighton. It starts at two termini in the capital, and , and the branches from each meet at , from where the route continues southwards via to the coast. The line ...
west branch out of , including through – the busiest station in Europe by railway traffic. The oldest part of the line, in the
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, was used from 1994 to 2007 by
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trains running out of .


History


London–Southampton (1830–1848)

The first written proposal for a railway line linking London and Southampton was published on 23 October 1830 by a group chaired by the Southampton MP Abel Rous Dottin. The following February, Francis Giles was commissioned to survey the route and a formal scheme, which also included the construction of new
dock The word dock () in American English refers to one or a group of human-made structures that are involved in the handling of boats or ships (usually on or near a shore). In British English, the term is not used the same way as in American Engl ...
s on the Solent, was presented at a public meeting on 6 April 1831. Giles, who was familiar with the west Surrey and north Hampshire area, having worked as an engineer for the Basingstoke Canal, examined potential routes via
Guildford Guildford () is a town in west Surrey, England, around south-west of central London. As of the 2011 census, the town has a population of about 77,000 and is the seat of the wider Borough of Guildford, which had around inhabitants in . The nam ...
and
Farnham Farnham is a market town and civil parish in Surrey, England, around southwest of London. It is in the Borough of Waverley, close to the county border with Hampshire. The town is on the north branch of the River Wey, a tributary of the ...
. However, his favoured alignment, via Basingstoke, was chosen to facilitate a future western branch to
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and
Bristol Bristol () is a City status in the United Kingdom, cathedral city, unitary authority area and ceremonial county in South West England, the most populous city in the region. Built around the River Avon, Bristol, River Avon, it is bordered by t ...
. His detailed survey was published on 5 December 1833 and the construction of the line from London to Southampton was approved in the London and South Western Railway Act 1834 on 25 July the following year. Under the terms of the 1834 act, the London and Southampton Railway company was authorised to issue shares to the value of £1 million (equivalent to £ million in ) and to borrow a further £330,000. Around half of the money was raised from businessmen from
Lancashire Lancashire ( , ; abbreviated ''Lancs'') is a ceremonial county in North West England. It is bordered by Cumbria to the north, North Yorkshire and West Yorkshire to the east, Greater Manchester and Merseyside to the south, and the Irish Sea to ...
, with much of the remainder provided by landowners from south Hampshire. Giles had estimated that his route would take three years to build at a cost of £800,000–£900,000. A formal ceremony to mark the start of construction took place at Shapley Heath, near Winchfield, on 6 October 1834, and the contracts for the earthworks and bridges had been let by the end of that month. Giles's strategy was to use numerous small-scale, local contractors, with work taking place simultaneously on multiple sites along the route. By February 1836, just under had been finished, with a further completed by the end of August 1836. Shareholder dissatisfaction with progress led to Giles's resignation on 13 January 1837 and his replacement by
Joseph Locke Joseph Locke FRSA (9 August 1805 – 18 September 1860) was an English civil engineer of the nineteenth century, particularly associated with railway projects. Locke ranked alongside Robert Stephenson and Isambard Kingdom Brunel as one of the ...
. Locke assessed the progress of the construction works and estimated that around £1.7 million (£ million in ) would be required to complete the line. He dismissed many of the smaller contractors, awarding much of the remaining work to Thomas Brassey. He also instituted a more rigorous supervision system by his assistant engineers. On 30 June 1837, the London and South Western Railway Deviations Act 1837 was passed, enabling the company to raise further capital and authorising deviations to the route. On 21 May 1838, the first section of the South West Main Line, between and Woking Common, opened with intermediate stations at Wandsworth (later replaced by Clapham Junction), Wimbledon, Kingston (now Surbiton), Ditton Marsh (now Esher), Walton and Weybridge. The extension westwards to Shapley Heath (now Winchfield), with a station at Farnborough, opened on 24 September 1838. On 14 June 1839, the London and Southampton Railway adopted the new name of the
London and South Western Railway The London and South Western Railway (LSWR, sometimes written L&SWR) was a railway company in England from 1838 to 1922. Originating as the London and Southampton Railway, its network extended to Dorchester and Weymouth, to Salisbury, Exete ...
(LSWR). Four days earlier, the first trains had run from Winchester to a temporary terminus north of Southampton at Northern Road (now Northam). The extension from Shapley Heath to Basingstoke also opened on 10 June 1839, and the section between Basingstoke and Winchester, which required three tunnels, was finished in May the following year. The opening ceremony for the completed line from Nine Elms to Southampton took place on 11 May 1840, with a directors' train leaving London at 8 am and arriving at the permanent terminus, designed by
William Tite Sir William Tite (7 February 179820 April 1873) was an English architect who twice served as President of the Royal Institute of British Architects. He was particularly associated with various London buildings, with railway stations and cemetery ...
, around three hours later. The LSWR did not intend Nine Elms to be its permanent northern terminus, and in 1844 an extension of to a new station at Waterloo Bridge was authorised. Three years later, the company acquired the Richmond and West End Railway, which had been authorised to build its own tracks alongside the London–Southampton line between Clapham Junction and Waterloo. Construction of the line north of Nine Elms, known initially as the "Metropolitan extension", began on 11 July 1848. The four-track line was carried on a viaduct of 290 arches, which followed a sinuous path to avoid encroaching on
Vauxhall Gardens Vauxhall Gardens is a public park in Kennington in the London Borough of Lambeth, England, on the south bank of the River Thames. Originally known as New Spring Gardens, it is believed to have opened before the Restoration of 1660, being me ...
, the local gas works, and
Lambeth Palace Lambeth Palace is the official London residence of the Archbishop of Canterbury. It is situated in north Lambeth, London, on the south bank of the River Thames, south-east of the Palace of Westminster, which houses Parliament of the United King ...
. The new terminus, designed by Tite and with four platforms, was initially known by a variety of names including York Road, Waterloo Bridge and Waterloo. On the day that Waterloo was opened, the Nine Elms terminus closed to passengers and was replaced by Vauxhall station.


Southampton–Brockenhurst and Hamworthy–Weymouth (1844–1857)

In February 1844, a group of Dorset businessmen, led by Charles Castleman, a
solicitor A solicitor is a lawyer who traditionally deals with most of the legal matters in some jurisdictions. A person must have legally defined qualifications, which vary from one jurisdiction to another, to be described as a solicitor and enabled to p ...
from Wimbourne, proposed a railway line linking Southampton to Dorchester. Surveyed by William Moorsom, the Southampton and Dorchester Railway (S&DR) was to take an indirect route to serve as many towns as possible, and its sinuous nature gave rise to the nickname "Castleman's Corkscrew". In particular the line would run via Ringwood, bypassing Bournemouth, which was a small village at the time. Poole, with a population of only 6,000, would be served by a branch from a station at Hamworthy. Castleman hoped to persuade the LSWR to operate the route, but the company refused, fearing that it would not be able to build any further lines west of Salisbury if it accepted. Instead, the
Great Western Railway The Great Western Railway (GWR) was a History of rail transport in Great Britain, British railway company that linked London with the southwest, west and West Midlands (region), West Midlands of England and most of Wales. It was founded in 1833, ...
(GWR) agreed to run services using broad-gauge trains. Concerned at this development, the LSWR proposed a rival scheme, the Salisbury & Dorsetshire Railway, which would have paralleled much of Castleman's line. Both proposals were considered by the
Board of Trade The Board of Trade is a British government body concerned with commerce and industry, currently within the Department for Business and Trade. Its full title is The Lords of the Committee of the Privy Council appointed for the consideration of ...
, which favoured the S&DR, but which also indicated that the route should be standard gauge. The LSWR agreed to lease Castleman's line for an annual sum of £20,000 (equivalent to £ million in ). The Southampton and Dorchester Railway Act 1845 was granted royal assent on 21 July 1845 and, the following month, Samuel Morton Peto was contracted to build the line. Materials were shipped by sea to Poole and the first part to be completed was the section between Ringwood and Dorchester. Wet weather during the winter of 1846–1847 delayed the completion of the eastern half of the line. Difficulties encountered during the construction of Southampton Tunnel meant that the first public trains between Blechynden (close to the site of the present Southampton Central station) and Dorchester ran on 1 June 1847. The link to the LSWR opened on 29 July that year, allowing through running of trains between London and Dorset, albeit with a reversal at the Southampton terminus station. The initial timetable was five trains per day in each direction between Nine Elms and Dorchester, with the fastest services taking hours. The LSWR was authorised to acquire the S&DR in the London and South Western and Southampton and Dorchester Railways Amalgamation Act, passed on 22 July 1848. The Southampton and Dorchester Railway Act 1845 gave the LSWR running rights over the southern section of the Wilts, Somerset and Weymouth Railway. The line, which was taken over by the GWR in 1850, was laid with dual-gauge track between Dorchester and Weymouth to allow both companies' trains to operate. The first trains ran over the new line on 20 January 1857, although trains to and from Weymouth could not call at the LSWR's Dorchester station without reversal.


Brockenhurst–Hamworthy (1863–1893)

The section of the South West Main Line between Christchurch and Bournemouth was built as part of the Ringwood, Christchurch and Bournemouth Railway. The company had opened the first part of its line, between Ringwood and Christchurch, on 13 November 1862, but passenger numbers were low. The proposal to continue the line to the growing seaside resort of Bournemouth was authorised by the Ringwood, Christchurch and Bournemouth Railway Act 1863. Work on the extension began in late 1865, and the single line opened 14 March 1870. Until December 1872, Poole was served by a station on the western side of the Harbour Bridge. Through carriages to London had been introduced by the LSWR in May 1860, and the branch line had been doubled in 1863–1864. The second station to serve Poole opened on 2 December 1872 and was served at first only by
Somerset and Dorset Joint Railway The Somerset and Dorset Joint Railway (S&DJR, also known as the S&D, S&DR or SDJR), was an English railway line Joint railway, jointly owned by the Midland Railway (MR) and the London and South Western Railway (LSWR) that grew to connect Bat ...
trains. It was constructed as part of the Poole and Bournemouth Railway, initially an independent company, but taken over by the LSWR in July 1871. The extension to , including an intermediate station at Parkstone, opened on 15 June 1874. By 1881, the population of Bournemouth had reached 17,000. The town was served by two stations, neither of which was in the town centre. The LSWR proposed a new station, adjacent to the town hall, on a new railway between the two existing facilities. Local opposition to the proposed link resulted in its route being moved northwards, and plans for the central station were abandoned. Instead, a new Bournemouth East station, designed by William Jacomb with a roof, was constructed. It opened on 20 July 1885 and the new link line was commissioned on 28 September 1886. Pokesdown station, between Christchurch and Bournemouth East, opened on 1 July 1886. The South Western (Bournemouth & c.) Act 1883, passed on 20 August 1883, authorised the construction of a cut-off line between Brockenhurst and Christchurch, which would reduce the distance between the two by around compared to the existing route via Ringwood. The works included a new Christchurch station and the doubling of the single line between Christchurch and Bournemouth East, both completed on 30 May 1886. Progress on the cut-off line was hindered by poor weather in spring 1887, which flooded cuttings and damaged embankments. The direct Brockenhurst–Christchurch line opened about a year later than planned, on 5 March 1888, with intermediate stations at Sway, New Milton and Hinton. The initial timetable was nine services per day from London to Bournemouth East, with eight in the opposite direction. The fastest trains took around three hours to cover the between the capital and Bournemouth. Portion working was instituted, allowing trains to split at Brockenhurst, with the front sections running as express services to Weymouth and the rear sections operating as local stopping trains to Bournemouth. The Holes Bay Curve, authorised by the South Western Railway Act 1890, was constructed by
Lucas and Aird Lucas and Aird was a major civil engineering business operating in the 19th century. History The business was formed as a joint venture between Lucas Brothers and John Aird & Co. in 1870. The joint venture was dissolved in 1896. Major projects ...
and opened on 1 June 1893. The new link allowed London–Weymouth trains to bypass Ringwood, taking the shorter route via Bournemouth and Poole. Opening on the same day was the avoiding line at Branksome, which allowed trains to bypass Bournemouth West, eliminating the need for reversal.


Branchlines

The first line to branch from the London–Southampton route was the Eastleigh– line, opened on 29 November 1841. The line was intended to serve
Portsmouth Portsmouth ( ) is a port city status in the United Kingdom, city and unitary authority in Hampshire, England. Most of Portsmouth is located on Portsea Island, off the south coast of England in the Solent, making Portsmouth the only city in En ...
, which could be reached via a floating bridge from Gosport. The station at Eastleigh, originally known as "Bishopstoke", was designed by William Tite, and had opened on 10 June 1839 with the section of line between Basingstoke and Northern Road. A further junction at the station was added with the completion of the Eastleigh–Salisbury line, which opened to freight on 27 January 1847 and to passenger trains on 1 March of the same year. By 1850, four lines branching from the South West Main Line had opened to serve locations in west Surrey and east Berkshire. The Guildford Junction Railway, which diverged from the South West Main Line at Woking, opened on 5 May 1845 and was extended to on 15 October 1849. The line to
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was opened on 27 July 1846 and was extended to Windsor on 1 December 1849. The branch to Chertsey opened in February 1848 and the branch to Hampton Court opened in February 1949. On 13 November 1854, the
London Necropolis Company The London Necropolis Company (LNC), formally the London Necropolis & National Mausoleum Company until 1927, was a cemetery operator established by Acts of Parliament in the United Kingdom, Act of Parliament in 1852 in reaction to the crisis cau ...
opened a short branch west of Woking, allowing funeral trains from its London terminus to reach
Brookwood Cemetery Brookwood Cemetery, also known as the London Necropolis, is a burial ground in Brookwood, Surrey, England. It is the largest cemetery in the United Kingdom and one of the largest in Europe. The cemetery is listed a Grade I site in the Regist ...
. Further branches serving Surrey were opened over the next few decades including to Epsom (4 April 1859), to Farnham via Aldershot (2 May 1870). and to Guildford via (2 February 1885). New lines were also added in central Hampshire. When proposing its line in the 1830s, the London and Southampton Railway had intended to construct a branch from Basingstoke to the west. Although Parliament had withheld permission for a line to Bath and Bristol in 1835, a branch to Salisbury, authorised in the London and South-western Railway Company's Basingstoke and Salisbury Extension Act 1846, opened between Basingstoke and on 3 July 1854. The GWR completed its branch from Reading to Basingstoke in November 1848, but there was no direct connection with the South West Main Line until mixed-gauge tracks were brought into use on 22 December 1856. A junction to the north of Winchester was created in October 1865 with the opening of the Mid-Hants Railway from . Two decades later, the city gained a second station, , opened by the Didcot, Newbury and Southampton Railway (DN&SR) in May 1885, although the junction of the DN&SR with the South West Main Line was not completed until 1 January 1891. West of Southampton, the Lymington Railway Company opened the first part of its line from Brockenhurst to Lymington Town to paying passengers on 12 July 1858, and services on a second branch serving Romsey, the so-called Sprat and Winkle Line between Redbridge and Andover, began on 6 March 1865. The branch from Wareham to opened on 20 May 1885.


Four tracking and grade separation

Following the opening of Waterloo station and Nine Elms Viaduct, the next part of the South West Main Line to be four-tracked was the section from Wimbledon to New Malden Junction. Opened on 1 January 1869, the Kingston Further Extension (KFE) enabled trains from
Kingston-upon-Thames Kingston upon Thames, colloquially known as Kingston, is a town in the Royal Borough of Kingston upon Thames, south-west London, England. It is situated on the River Thames, south-west of Charing Cross. It is an ancient market town, notable as ...
to reach via . The new tracks ran from Kingston via a new station at Norbiton, passing beneath the South West Main Line before turning to run parallel with it for around . The junction at Raynes Park was altered so that the line to Epsom, which had previously been directly connected to the main line, joined the KFE instead. A junction at Wimbledon was installed to allow the existing Waterloo–Epsom trains and a new Waterloo–Waterloo "roundabout" service via the Kingston loop to run. For the next decade, the KFE operated as a two-track railway, but on 24 April 1880 it was more closely integrated with the South West Main Line, when a new junction was created at the west end of Malden station. In Spring 1884, the lines were redesignated from a paired-by-use to a paired-by-direction system, meaning that the original South West Main Line tracks carried trains towards Waterloo and the KFE tracks only carried trains for Surrey, Hampshire and the south coast.
Grade-separated In civil engineering (more specifically highway engineering), grade separation is a method of aligning a junction of two or more surface transport axes at different heights ( grades) so that they will not disrupt the traffic flow on other tr ...
junctions at Raynes Park (for the Epsom line) and at Malden (for the Kingston loop line) were opened on 16 March 1884. The four-track section was extended at both ends in the 1880s. Quadrupling was completed between Malden and Surbiton in 1882, and a second up line was opened between Clapham Junction and Wimbledon the following year, with an additional down line commissioned on the same section in March 1884. The stretch from Surbiton to Hampton Court Junction was widened to four tracks on 29 July 1883, in part to accommodate traffic using the New Guildford line, which opened in February 1885. The approaches to Waterloo were widened in 1891, requiring Vauxhall station to be rebuilt with seven tracks, served by three island platforms. Shortly before the end of the century, the section of the South West Main Line from Basingstoke to Worting Junction, where the line to Salisbury diverges, was expanded to four tracks. Grade separation at Worting was achieved with the construction of Battledown Flyover, which opened on 30 May 1897. Four-tracking of the South West Main Line between Woking and Basingstoke began at the end of the 19th century. The section between the Sturt Lane Junctions and the eastern approach to Farnborough was completed on 4 June 1899. As part of the widening works, Pirbright Junction, where the Alton line diverges, was grade separated and the new flyover for Aldershot to London trains opened on 30 June 1901. The project also required the lengthening of Frimley Aqueduct, blocking the Basingstoke Canal for a five-month period, and the relocation of Fleet station around to the west. Rebuilding Basingstoke station, a major bottleneck on the line, was finished on 18 December 1904 and the quadrupling of the Woking–Basingstoke section was completed on 5 March 1905. Four-tracking of the South West Main Line between Hampton Court Junction and Woking took place around the same time. First to be quadrupled was the section from Byfleet to Woking, completed on 15 Sept 1901. Two additional tracks had been commissioned at Esher station on 1 April 1888, and the stretch from there to Hampton Court Junction was widened to four tracks on 27 April 1902. A week later, on 4 May, the widening of the section from St Denys to Northam was also completed. Quadrupling between Esher and Byfleet was undertaken in stages and was finally completed on 5 June 1904. The work included the creation of a grade-separated junction at Byfleet. Further widening between Waterloo and Clapham Junction was undertaken, including the expansion of Vauxhall station to eight platforms and eight tracks. A new down line had been commissioned from there to Wandsworth Road on 5 July 1903, and a new up main relief line was opened between Waterloo and Vauxhall on 24 January 1909. Further grade-separation projects were undertaken between Surbiton and Esher. A diveunder, taking the up New Guildford line under the South West Main Line, was commissioned on 21 October 1908 for the use of trains from Cobham to Waterloo. In order to accommodate the increased frequency of trains post-electrification, a flyover for trains heading to Hampton Court was constructed, opening on 4 July 1915. The requirement for terminating suburban trains to cross the station throat at Waterloo to access the slow line platforms had been a source of congestion ever since the tracks on the quadrupled sections of the line had been paired by direction. In 1914, to resolve these operating constraints, the LSWR proposed constructing a flyover in the Vauxhall area, but the outbreak of the First World War meant that the project did not progress. Two decades later, the Southern Railway proposed a similar scheme to the north of Wimbledon station. The flyover, which carries stopping trains for London over the fast tracks, has a total length of and was completed in 1936.


Signalling

The first signals were introduced to the South West Main Line in 1840. Taking the form of pole-mounted discs, they could be rotated to indicate whether the line ahead was clear or blocked. When presented edge-on to an approaching train, the driver was allowed to proceed, whereas if the face of the face of the disc was visible, the driver was required to stop. By the end of 1847, an
electrical telegraph Electrical telegraphy is point-to-point distance communicating via sending electric signals over wire, a system primarily used from the 1840s until the late 20th century. It was the first electrical telecommunications system and the most wid ...
system had been installed along the entire length of the line, giving railway staff the ability to communicate the positions of trains. " signals" were introduced at Weybridge and Farnborough stations in 1848. Installed around from the platforms, they were used to stop approaching trains, if the line beyond was occupied. Following a serious accident at in 1864, the block system of working was introduced between London and Woking, and between Eastleigh and Southampton. The final disc signals were replaced with semaphore signals in 1866. In March 1895, the LSWR board agreed to install
William Robert Sykes William Robert Sykes (1840–1917) was a British engineer from London, known for his work in railway signalling and other safety devices. He is noted for the invention of the Sykes 'Lock and block' interlocking system of points and signals. Ca ...
's system of interlocking mechanical block signals between Earlsfield and Hampton Court Junction at a cost of £1,975 (equivalent to £ in ). Between 1904 and 1907, automatic pneumatically operated signals were installed between Woking and Basingstoke. Colour-light signals were introduced to the South West Main Line between London and Hampton Court Junction in 1936. Between Waterloo and Nine Elms, three-aspect signals were installed, with four-aspect signals on the rest of the section. The project included a reduction in the number of signal boxes from 23 to 13 and, where necessary, the new signals were equipped with junction route indicators. Work at the western end of the route transferred the control of the line from Dorchester to Weymouth to a new panel signal box at Dorchester in 1959. A new panel box was also opened at Brockenhurst in 1964. Resignalling in the Southampton area at the start of the 1980s transferred control of the station to Eastleigh Panel Box. The project included the installation of colour-light signals, and the closure of Southampton signal box, which had opened in June 1935. Two projects in the early 21st century eliminated the final semaphore signals on the line. The 60-lever Bournemouth Central signal box, which had opened in 1928, was closed in 2003 with control transferred to the new Bournemouth Area Signalling Centre. The Poole-Wool resignalling project was completed in May 2014 and resulted in the closure of mechanical signal boxes at Poole, Hamworthy, Wareham and Wool.


Infrastructure


Track

Between London Waterloo and Clapham Junction, the line has eight tracks. It runs over the Nine Elms to Waterloo Viaduct for much of its length. It crosses beneath the Chatham Main Line where the
Brighton Main Line The Brighton Main Line is a railway line in southern England linking London to Brighton. It starts at two termini in the capital, and , and the branches from each meet at , from where the route continues southwards via to the coast. The line ...
runs alongside it on the southern side. At Clapham Junction, some of these tracks leave on the Waterloo to Reading Line and the remaining tracks are reduced to four. The Brighton Line, which also has four tracks, separates from it shortly afterwards. The four tracks initially have a pair of "slow" tracks to the east with the two "fast" tracks on the western side. This arrangement continues to north of
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where a flyover transfers the northbound slow line across the fast lines, leaving the inner tracks being used for the fast services and the stopping services using the outer tracks. This arrangement continues to Worting Junction, just after
Basingstoke Basingstoke ( ) is a town in Hampshire, situated in south-central England across a valley at the source of the River Loddon on the western edge of the North Downs. It is the largest settlement in Hampshire without city status in the United King ...
. Many stations on this section had island platforms which have since been removed - this is evident with wide gaps between station platforms at stations such as Winchfield. The island platforms survive at
New Malden New Malden is a suburban area in southwest London, England. It is within the Royal Borough of Kingston upon Thames and the London Borough of Merton, and is from Charing Cross. Neighbouring localities include Kingston upon Thames, Kingston, Norb ...
,
Esher Esher ( ) is a town in the borough of Borough of Elmbridge, Elmbridge in Surrey, England, to the east of the River Mole, Surrey, River Mole. Esher is an outlying suburb of London, close to the London–Surrey border; with Esher Commons at its ...
and
Walton-on-Thames Walton-on-Thames, known locally as Walton, is a market town on the bank (geography), south bank of the River Thames, Thames in northwest Surrey, England. It is in the Borough of Elmbridge, about southwest of central London. Walton forms part ...
, although mothballed and out of use. The line continues as double-track to
Winchester Winchester (, ) is a City status in the United Kingdom, cathedral city in Hampshire, England. The city lies at the heart of the wider City of Winchester, a local government Districts of England, district, at the western end of the South Downs N ...
but expands to three tracks through Shawford station with one up platform and fast and slow down platforms. There are four tracks from Shawford to Eastleigh. The line from
Romsey Romsey ( ) is a town in the Test Valley district of Hampshire, England. The town is situated northwest of Southampton, southwest of Winchester and southeast of Salisbury. It sits on the outskirts of the New Forest, just over northeast of ...
via
Chandler's Ford Chandler's Ford (originally The Ford and historically Chandlersford) is a largely residential area and civil parish in the Borough of Eastleigh in Hampshire, England. It had a population of 21,436 according to the 2011 United Kingdom census, 20 ...
trails in just north of Eastleigh which is also the junction for the Fareham line. The line returns to double track until St Denys where the West Coastway Line trails in. At Northam the original route to Southampton Terminus carries on south towards Eastern Docks and the main route curves west to enter a tunnel through to Southampton Central station. The line remains double-tracked most of the way to Weymouth, but there is a single-track section between Moreton and Dorchester South which constrains capacity.


Electrification

The first part of the LSWR to be electrified was the Waterloo & City Railway, now the Waterloo & City Line, which operated electric trains from the outset when it opened in mid-1898. Over the next five years, the company investigated electrifying some of its surface routes and, in 1903, the resident engineer, J. Jacomb-Hood, told the board that running an intensive electric service over the slow lines between Waterloo and Hampton Court Junction would be no more expensive than the existing steam operation. On 4 December that year, the LSWR signed an agreement with the
District Railway The Metropolitan District Railway, also known as the District Railway, was a passenger railway that served London, England, from 1868 to 1933. Established in 1864 to complete an " inner circle" of lines connecting railway termini in London, the ...
to electrify the
Hammersmith Hammersmith is a district of West London, England, southwest of Charing Cross. It is the administrative centre of the London Borough of Hammersmith and Fulham, and identified in the London Plan as one of 35 major centres in Greater London. It ...
–Richmond and East Putney–Wimbledon lines. The District Railway's electric trains began running to Richmond and Wimbledon in August 1905. Over the course of the next six years, passenger numbers on the LSWR declined by million and, in 1912, the company estimated that its annual income would have been around £100,000 higher, had its suburban lines been electrified. That year, the company authorised the laying of the third rail along , and the first electric trains operated in public service to on 30 January 1916, running along the South West Main Line between Waterloo and New Malden Junction. Electricity was supplied from a 25 kW power station at Durnsford Road, Wimbledon, completed in 1915. The third rail was extended to Hampton Court Junction, where a flyover was constructed, and electric trains began running to Hampton Court and to on 18 June and 20 November 1916 respectively. As part of the works, platforms 1–6 and 16 were electrified at Waterloo, and substations were installed at Waterloo, Clapham Junction and Raynes Park. The total cost of the first phase of LSWR suburban electrification, including both infrastructure and rolling stock, was £1.37 million (equivalent to £ million in ). As a result of the project, passenger numbers on the LSWR grew from 23.3 million in 1915 to 29 million in 1916, and to 33 million in 1917. The
Surrey Surrey () is a Ceremonial counties of England, ceremonial county in South East England. It is bordered by Greater London to the northeast, Kent to the east, East Sussex, East and West Sussex to the south, and Hampshire and Berkshire to the wes ...
section, about half of which has become
Greater London Greater London is an administrative area in England, coterminous with the London region, containing most of the continuous urban area of London. It contains 33 local government districts: the 32 London boroughs, which form a Ceremonial count ...
, was electrified as far west as Pirbright Junction (for Alton) before World War II. It was completed, using the 750 V DC third-rail system, by the London & South Western Railway or the Southern Railway, its successor. Electrification of the South West Main Line between Sturt Lane (near
Frimley Frimley is a town in the Borough of Surrey Heath, in Surrey, England. It lies approximately south-west of central London. The town is of Anglo-Saxon settlement of Britain, Saxon origin, although it is not listed in Domesday Book of 1086. Hi ...
) and Bournemouth was authorised in September 1964. Installation of
overhead line An overhead line or overhead wire is an electrical cable that is used to transmit electrical energy to electric locomotives, Electric multiple unit, electric multiple units, trolleybuses or trams. The generic term used by the International Union ...
s was considered, but British Rail instead decided to use the third-rail system which was considered to have a lower upfront cost. An electrical feed from the National Grid was installed at Basingstoke, with power distributed via a network of 19 substations. The project included the replacement of jointed track with continuous welded rail. Regular electric trains from London began operating in public service to Basingstoke on 2 January 1967 and to Bournemouth on 10 July 1967. The final steam-hauled public service between Waterloo and Southampton ran on 8 July 1967. In the same month, the locomotive shed at
Nine Elms Nine Elms is an area of south-west London, England, within the London Borough of Wandsworth, with some parts (including the Nine Elms tube station, tube station) extending into the neighbouring London Borough of Lambeth. It lies on the River Thame ...
– the last main-line steam shed in England – was closed. Rolling stock constructed or modified and rebuilt under the 1967 electrification project consisted of: * 11 4-Rep 4-car powered tractor
electric multiple unit An electric multiple unit or EMU is a multiple-unit train consisting of self-propelled carriages using electricity as the motive power. An EMU requires no separate locomotive, as electric traction motors are incorporated within one or a number o ...
(EMU) * 28 4-TC 4-car unpowered multiple units * 3 3-TC 3-car unpowered trailer multiple units * 4 spare trailer coaches * 20 4-Vep EMUs * 10 HB Class 74 electro-diesel locomotives * 19 KB Class 33/1 diesel-electric locomotives * 4 Class 12 diesel shunters * 3 three-car de-icing EMUs The ''4-Rep'' tractor units' 3001–3011 motor coaches were newly built, as were the complete ''4-Vep'' units 7701–7720, but the ''4-Rep'' trailer coaches and all cars in the ''4-TC'' and ''3-TC'' sets 401–428 and 301–303 were conversions from locomotive-hauled stock; the four spare trailer coaches were two RU, one BFK and one DTSO. It was planned originally that a 3-car single-ended push-pull trailer set formed DTC+BFK+RU would work with a Class 74 to cover ''4-Rep'' heavy maintenance, but this formation never operated and was replaced by the ''8-Vab'' unit 8001; the three cars remained as spares. The other RU was deployed on special trains with TC units when needed. Class 74 were heavy rebuilds of Class 71
electric locomotives An electric locomotive is a locomotive powered by electricity from overhead lines, a third rail or on-board energy storage such as a Battery (electricity), battery or a supercapacitor. Locomotives with on-board fuelled prime mover (locomotive), ...
; Class 33/1 were a push-pull modification of 33/0. The Class 12 shunters were air brake fitted and intended as depot shunters and station pilots. The de-icing units were formed of three pairs of ''2-Hal'' and ''4-Lav'' EMU motor coaches coupled back to back and adapted for electro-pneumatic brakes. In later days, there were several changes to allocations and formations. From then until 1988, trains on the Bournemouth to Weymouth section operated a push-pull system. One or two ''4-TC'' units would be propelled from London to
Bournemouth Bournemouth ( ) is a coastal resort town in the Bournemouth, Christchurch and Poole unitary authority area, in the ceremonial county of Dorset, England. At the 2021 census, the built-up area had a population of 196,455, making it the largest ...
by a ''4-REP'' unit, controlled from the leading cab of the former. At Bournemouth, one or both of the ''4-TCs'' would continue over the non-electric line to Weymouth, hauled by a Class 33/1 diesel locomotive. Trains from Weymouth would follow the same procedure in reverse. Electrification of the South West Main Line between Bournemouth and Weymouth was authorised in January 1986, and work on the £53 million project (£ million in ) began in October that year. To reduce costs, a stretch of line was singled between Moreton and Dorchester South, and the capacity of the 11 kV supply from the National Grid limited train lengths to a maximum of five coaches. The third rail was energised on 11 January 1988, and public electric services began on 16 May that year. The units, ordered as part of the project, reduced the journey time between Waterloo and Weymouth by 25 minutes. and trains were introduced between 2004 and 2006.


Services

The majority of passenger services are currently operated by
South Western Railway South Western Railway Limited, trading as South Western Railway (SWR), is the British state-owned train operating company that took over the services of the South Western Railway (2017–2025), operator of the same name from FirstGroup and MTR ...
.
CrossCountry CrossCountry (legal name XC Trains Limited) is a British train operating company owned by Arriva UK Trains, operating the current CrossCountry franchise. The CrossCountry franchise was restructured by the Department for Transport (DfT) in 2006, ...
operates the Bournemouth – Manchester services travelling on the line between Bournemouth and Basingstoke. In addition,
Great Western Railway The Great Western Railway (GWR) was a History of rail transport in Great Britain, British railway company that linked London with the southwest, west and West Midlands (region), West Midlands of England and most of Wales. It was founded in 1833, ...
and Southern also operate services at Southampton Central, which use a section of South West Main Line to access Southampton. In more detail, London Waterloo – Weymouth services run on the whole length of South West Main Line, and other intercity services which run on a significant portion of the line include: * London Waterloo – Portsmouth Harbour (via Eastleigh) services, branching off at Eastleigh as an indirect service * London Waterloo – Salisbury and Exeter St Davids services, branching off at Basingstoke * London Waterloo – Portsmouth services, branching off at Woking * Bournemouth – Manchester CrossCountry services, branching off at Basingstoke for the Reading to Basingstoke Line to Reading Other services from London Waterloo also run on a section of South West Main Line, except those using the Waterloo–Reading line in the direction of
Richmond Richmond most often refers to: * Richmond, British Columbia, a city in Canada * Richmond, California, a city in the United States * Richmond, London, a town in the London Borough of Richmond upon Thames, England * Richmond, North Yorkshire, a town ...
.


Future development

In July 2011, Network Rail in its London & South East Route Utilisation Strategy (RUS) recommended adding a fifth track to the four-track stretch of line between Clapham Junction and Surbiton. This was found to be feasible within the existing land (rail corridor), and was seen as the most practicable way of providing more capacity on the route. It would permit up to eight additional trains to run in the peak hour, for a maximum of 32 trains in this stretch. The scheme would also entail more flexible track use, modifying one Windsor Line track to permit use by mainline trains. Options rejected in the RUS as not viable included double-deck trains, building a flyover at Woking, and introducing 12- or 16-car trains.


Major accidents and incidents

* 2 Apr 1842: Wallers Ash Tunnel, between Micheldever and Winchester, collapsed. Four maintenance workers, who had been attempting to shore up the tunnel roof, were killed. * 11 September 1880: A locomotive waiting to access Nine Elms depot was struck by a passenger train south of Vauxhall station due to a signaller's error. Seven people were killed. * 25 May 1933: A derailed passenger train at Raynes Park was struck by a passing train on the adjacent track. Five people were killed. * 26 November 1947: A passenger train ran into the back of a second train that had stopped at a red signal at
Cove A cove is a small bay or coastal inlet. They usually have narrow, restricted entrances, are often circular or oval, and are often situated within a larger bay. Small, narrow, sheltered bays, inlets, creek (tidal), creeks, or recesses in a coast ...
near Farnborough. Two people were killed. * 12 December 1988, Clapham Junction rail crash: A passenger train ran into the rear of a second train south of Clapham Junction, after faulty wiring caused a signal to display an incorrect proceed aspect. A third train collided with the wreckage. The accident occurred shortly after 8 am on a weekday morning and 35 people were killed.


Listed buildings and structures


Stations

There are seven Grade II-listed stations on the South West Main Line:


Other buildings and structures

Other listed buildings and structures associated with the South West Main Line include (all Grade II-listed):


Notes


References


Bibliography

* * * * * * * * * * * * * * * * * * * * * * *


External links


Basingstoke's Railway HistoryNetwork Rail's Route Utilisation Strategy for the South West Main Line
{{Current rail infrastructure projects in the United Kingdom Transport in the London Borough of Lambeth Transport in the London Borough of Wandsworth Transport in the London Borough of Merton Transport in the Royal Borough of Kingston upon Thames Rail transport in Surrey Rail transport in Hampshire Rail transport in Dorset Railway lines opened in 1840 Railway lines in London Railway lines in South East England Railway lines in South West England Standard gauge railways in England