The North Downs Line is a railway line in South East England. It runs for from in Berkshire to in Surrey. It is named after the North Downs, a range of chalk hills that runs parallel to the eastern part of the route. The name was introduced in 1989 by Network SouthEast, the then operator. The North Downs Line serves the settlements in the Blackwater Valley as well as the towns of Guildford, Dorking and Reigate. It acts as an orbital route around the south-west of London and has direct connections to the Great Western Main Line at Reading, the Waterloo–Reading line at , the Alton line at , the Portsmouth Direct line at and the Brighton Main Line at Redhill.
Three different operators run passenger services on the North Downs Line. Great Western Railway runs services along the entire length of the line from Reading to Redhill, the majority of which continue along the Brighton Main Line to . Southern trains between and use a section west of Redhill. South Western Railway services between the capital and Reading use the line west of Wokingham and the same company operates between Guildford and en route to .
The majority of the North Downs Line was constructed by the independent Reading, Guildford and Reigate Railway company (RG&RR), although the section between Guildford and Ash Junction was built by the London and South Western Railway. The line opened in 1849 and services were run from the outset by the South Eastern Railway, which took over the RG&RR in 1852. Three sections of the line were electrified by the Southern Railway in the 1930s although around remain unelectrified. In the early 21st century, infrastructure works to increase the capacity of the line were undertaken, including the provision of new platforms at Reading and Redhill.
Route Overview The North Downs Line is a railway line in South East England. It links Reading railway station on the Great Western Main Line in Berkshire to on the Brighton Main Line in Surrey. It serves the settlements in the Blackwater Valley on the borders of Hampshire, Surrey and Berkshire, as well as the Surrey towns of Guildford, Dorking and Reigate. It acts as an orbital route bypassing the south-west of London and has direct connections to the Waterloo–Reading line at , the Alton line at and the Portsmouth Direct line at . The 2015 "Surrey Rail Strategy" noted that 56% of passengers on the route connect to services on other railway lines and that a quarter of journeys either start or end at Reading. Around 13% of passengers travel to or from .
The name "North Downs Line" was first used in 1989 by Network SouthEast, the then operator of the line. Between Redhill and Ash, the line runs roughly parallel with the North Downs, a range of chalk hills that runs from Farnham to the White Cliffs of Dover. Between Ash and Reading, the line crosses the sands, gravels and clays of the London Basin. The steepest gradients, 1 in 96, and the summit of the line are near , where the route crosses the watershed between the Rivers Mole and Wey in Surrey. The distances along the line between Redhill (22 miles 40 chains) and Shalford Junction (41 mi 60 ch), and between Ash Junction (48 mi 34 ch) and Reading (68 mi 68 ch) are measured from station in London.
The North Downs Line is double track for the entirety of its length and has a maximum operational line speed of for passenger trains. Three sections of the line, RedhillReigate, GuildfordAldershot South Junction and WokinghamReading, are electrified using the 750 V DC third-rail system. Two sections, ReigateShalford Junction and Aldershot South JunctionWokingham, together totalling , are unelectrified. The line has a W6 loading gauge, and overnight engineering possessions of up to hours are available. In 2006, Network Rail classified the North Downs Line as "congested", but, following the construction of new infrastructure, this status was revoked in 2023.
Reading to Guildford
The Reading to Guildford section of the North Downs Line is in length and has 13 stations in total. Reading and Guildford stations are managed by Network Rail and have 15 and 7 operational platforms respectively. The other 11 stations have two platforms each. , , , Wokingham, Ash and stations are managed by South Western Railway (SWR). , , , and stations are managed by Great Western Railway (GWR). The passenger train services that use this section of the North Downs Line are: Reading to Redhill and , operated by GWR using and units Reading to , operated by SWR using and units and to Guildford, operated by SWR using units
West of Wokingham Junction and east of Aldershot South Junction, this part of the line is electrified using the 750 V DC third-rail system, leaving an unelectrified central section. Most services on the North Downs Line use platforms 4, 5 and 6 at Reading station, but access to other platforms is possible. The Reading station area is controlled from Thames Valley rail operating centre, the line from Earley to North Camp is controlled by Basingstoke rail operating centre, and the section from North Camp is controlled by Guildford signal box. The majority of this section has a line speed of with the exception of the approaches to Reading, Wokingham and Guildford stations, and a restriction at Ash Junction where the line curves sharply. The steepest gradient, to the west of Guildford, is 1 in 100.
The Waterloo–Reading line diverges from this part of the North Downs Line at Wokingham Junction, and a spur to the Alton line joins at Aldershot South Junction. In addition, the line passes beneath the South Western Main Line at Farnborough, but there is no longer a junction between the two. This section passes over two navigable waterways, the River Kennet and the Basingstoke Canal, as well as the unnavigable River Loddon and its tributary, the Blackwater.
Stations between Reading and Guildford StationMileageNumber of platformsManaging companyTrains operated byOpening dateOriginal nameRef.from via 15Network Rail GWRSWRCrossCountryElizabeth line from Charing Cross via Redhill2SWRSWR from Charing Cross via Redhill 2SWRSWR from Charing Cross via Redhill 2SWRSWRGWRSindlesham and Hurst from Charing Cross via Redhill 2SWRSWRGWR from Charing Cross via Redhill 2GWRGWRWellington College from Charing Cross via Redhill2GWRGWR from Charing Cross via Redhill 2GWRGWR from Charing Cross via Redhill 2GWRGWRFarnborough from Charing Cross via Redhill 2GWRGWR from Charing Cross via Redhill2SWRSWRGWR from via 2SWRSWRGWR from London Waterloo via Woking7Network RailSWRGWR
Shalford Junction to Redhill
Between Guildford and Shalford Junction, GWR trains use the Portsmouth Direct line to travel between the two parts of the North Downs Line. The route passes through two tunnels, Guildford Chalk Tunnel and St Catherine's Tunnel. Reversible working is available on the down line on this section of track.
The Shalford Junction to Redhill section of the North Downs Line is long and has eight stations in total. Reigate and Redhill stations are managed by Southern, but the remaining six stations (, , Gomshall, , and ) are managed by GWR. Redhill has four platforms, but the other seven stations have two each. The passenger train services that use this section of the North Downs Line are: Reading to Redhill and Gatwick Airport, operated by GWR Reigate to via Redhill, operated by Southern
Much of this part of the North Downs Line runs immediately to the south of the North Downs escarpment, although the route deviates to the south between Chilworth and Gomshall to avoid Albury Park. Only the section between Reigate and Redhill is electrified. Between Shalford Junction and Gomshall, the line is controlled from Guildford signal box and the majority of the route to the east is controlled by Reigate signal box. Redhill railway station and its approaches are controlled by Three Bridges rail operations centre. The maximum speed on this part of the North Downs Line is .
The route crosses the Mole Valley Line immediately to the east of Dorking Deepdene, but there is no longer a junction between the two. The navigable River Wey is crossed at Shalford via a steel truss bridge, which replaced the original wooden bridge in 1902. The North Downs Line crosses the River Mole on a five-arch, brick viaduct, built when the line was constructed in the late 1840s. The A24 dual carriageway at Dorking is crossed on a steel bridge, installed in 1964.
Stations between Shalford Junction and Redhill StationMileagefrom via Number of platformsManaging companyTrains operated byOpening dateOriginal nameRef.2GWRGWR 2GWRGWR 2GWRGWR 2GWRGWRDorking2GWRGWRBox Hill and Leatherhead Road2GWRGWR 2SouthernSouthernGWR4SouthernSouthernThameslinkGWR (relocated 15 April 1844)Reigate
History Proposal and authorisation The Reading, Guildford and Reigate Railway company (RG&RR) was formed in August 1845. It was led initially by Frederick Mangles, a banker from Guildford, and most of the board members were businessmen from London and Surrey. The company's stated objective was to build a line linking the three towns in its name to "secure through traffic passing between the West, North and Midlands and the Channel Ports avoiding the congestion of London and thus saving time, distance and expense."
The engineer, Francis Giles, was commissioned to survey the line. His route, presented to the board in January 1846, had an estimated cost of £710,000 (equivalent to £ million in ) and was to be double track throughout. It would run from the Great Western Main Line at Reading to the Brighton Main Line at Reigate Junction (later Redhill). Between Dorking and Gomshall, Giles's route required the use of the proposed London & Portsmouth Direct Atmospheric Railway. The approaches to Guildford would use part of the London and South Western Railway (LSWR) lines to and .
Negotiations with other railway companies began at the start of 1846. By mid-January, the RG&RR had bought out the rival Reading and Reigate Company, promoted by David Mocatta, which had proposed a line with similar aims. That March, it agreed terms to run over the LSWR tracks from Shalford Junction to Guildford. In the same month, the South Eastern Railway (SER), which had wanted to build its own short branch from Reigate Junction to Dorking, offered to operate the line. A bill was prepared for Parliament and the RG&RR was authorised on 16 July 1846, the same day that the LSWR's line from Guildford to Alton was approved. The act gave the RG&RR the powers to construct the section of the line from Dorking to Gomshall, if it was not built in time by the London & Portsmouth Direct Atmospheric Railway Company.
Route alterations and construction
Francis Giles died in March 1847 and his position as surveyor and engineer was taken, on a temporary basis, by Robert Stephenson. Stephenson began to make changes to Giles's scheme, primarily to reduce costs. Around £3000 was to be saved by simplifying the link to the South Western Main Line at Farnborough, eliminating the north–west curve, leaving only the north–east curve to be built. At Reading, Giles had proposed running alongside the Great Western Main Line on a widened embankment, but Stephenson argued that the RG&RR should build a separate station (later known as ) instead of sharing the Great Western Railway (GWR) facilities. Minor alterations were also made to the route in the Gomshall, Albury and Ash areas. A deviations bill was submitted to Parliament and was given royal assent on 22 July 1847.