Brighton main line

Govia Thameslink Railway (GTR), which operates the Southern, Gatwick Express and Thameslink brands, operates the majority of passenger services on the line, including all services to and from the two London Terminals:[2][3]

• Gatwick Express runs non-stop services between London Victoria and Gatwick Airport; some of these are extended to/from Brighton.
• Thameslink runs services on the Brighton main line to and from London Bridge, from which they continue along the Thameslink core section through central London (via London Blackfriars and London St Pancras International) and beyond to destinations north of London, including Peterborough, Cambridge and Bedford. Services between Three Bridges and Bedford operate 24 hours a day.
• All other GTR services, including those between London Victoria and Gatwick Airport that call at intermediate stations, are branded as Southern.

The only two other train operating companies that operate on the line are:

• London Overground, operated by Transport for London, which runs stopping services between Norwood Junction and New Cross Gate, and then along the East London Line towards Highbury & Islington, avoiding the central London area;[4]
• Great Western Railway, which serves trains between Gatwick Airport and Redhill, and then along the North Downs line towards Guildford, Wokingham and Reading.[5]

Normal-running and 'bi-directional' signals outside Haywards Heath tunnel

Between Balcombe Tunnel Junction and Preston Park, the line reduces from four tracks to two, with only a short quadruple-tack passing loop between Copyhold Junction and Haywards Heath South Junction (through Haywards Heath station).[6] A broken-down train in this section causes the most disruption; therefore, to minimise the effects, the line is divided into four sections of bi-directional signalling, which allows trains to cross over and run on the right-hand track (i.e. "the wrong way"). These are:[7][8]

• Balcombe Tunnel Junction to Copyhold Junction;
• Copyhold Junction to Haywards Heath South Junction (outer tracks only);
• Haywards Heath South Junction to Keymer Junction;
• Keymer Junction to Preston Park station.

At the passing loop through Haywards Heath, the two inner tracks are only signalled bi-directionally south of Haywards Heath station itself, which allows trains to reverse at the station to/from the south. North of the station these tracks can only be used in their respective directions.[7][8]

There were six original proposals to build a railway between London and Brighton. The London and Brighton Railway (L&BR) emerged with an Act of Parliament of 15 July 1837 after a prolonged and expensive battle, with the most direct route, from the London and Croydon Railway (L&CR) at Norwood Junction to Brighton, using the L&CR from Norwood to London Bridge. A condition required by Parliament was that the railway should share its line between Croydon and Redhill with the South Eastern Railway main line to Dover. This clause gave rise to 60 years of disputes between the two companies.

Land use between London and Brighton was largely rural. The line was planned to traverse the North Downs, the Wealden ridge and the South Downs while avoiding steep gradients.

Owing to the difficult terrain and relatively sparse population between Croydon and Brighton, the line by-passed several towns and villages on the London-Brighton road, such as Reigate and Crawley. Even so, it required substantial earthworks, notably through the North Downs at Merstham, with one of the largest cuttings in Britain; seven tunnels (Merstham, Balcombe, Haywards Heath, Clayton and Patcham initially, then Quarry and Redhill which were constructed later); and several embankments. To avoid steep gradients or detours, the 1,475-foot-long (450 m), maximum 96-foot-high (29 m) Ouse Valley Viaduct was built near Balcombe.

The line opened in two stages:

12 July 1841: Norwood Junction to Haywards Heath.

21 September 1841: to Brighton.

The branch line from Brighton to Shoreham-by-Sea was finished on 12 May 1840, before the main line, as it did not involve significant civil engineering works (all the materials arrived by sea from mainland Europe). The Newhaven section did not materialise until 1846, when the Brighton - Hastings line was opened by the Brighton Lewes and Hastings Railway. A few weeks later the L&CR, the L&BR and other railways in Sussex amalgamated to form the London, Brighton and South Coast Railway (LB&SCR).

A branch line from Norwood to Crystal Palace was built in 1851, extending to Sydenham in 1854, Balham and Wandsworth in 1856, Battersea in 1858, and London Victoria in 1860. A cut-off line reducing the distance between East Croydon and Balham opened in 1862.

There were frequent disputes resulting from the companies' sharing of the busy section between East Croydon and Redhill. The LB&SCR owned the section between East Croydon and Coulsdon North, and the SER (later the South Eastern and Chatham Railway) from Coulsdon South to Redhill. Eventually the LB&SCR built the "Quarry Line", a by-pass for express trains between Coulsdon North and Earlswood, avoiding Redhill. It opened on 8 November 1899 (1 April 1900 for passengers trains).

The line was the first UK main line to be electrified throughout. The LB&SCR electrified its South London Line on 1 December 1909 using an overhead high-tension single-phase system; within three years the line from Victoria to Selhurst railway station was also converted. In 1921 plans were drawn up to extend overhead electrification to Brighton,.[9] In 1925[10] it was extended toward the edge of today's Greater London at Coulsdon North, before being scrapped by the amalgamated operator under the 1923 grouping: Southern Railway which decided to standardise on the third-rail system of the former London and South Western Railway. In 1928/29 the lines began conversion to third-rail operation.

The change to third rail electrification was in place southward to Coulsdon North by 1929[11] – to Three Bridges in the north of Sussex in July 1932, then reaching Brighton and West Worthing on the coast on 1 January 1933.[12]

The third rail is electrified at 750 V DC, and in the early part of the 21st century had its power supply upgraded for the introduction of Electrostar stock by Southern. Traction current supply is supervised by Lewisham, Selhurst and Brighton electrical control rooms which will be superseded by the Three Bridges ROC.[13]

• In the Clayton Tunnel rail crash on 25 August 1861, a signaller mistakenly allowed a passenger train into the tunnel before the previous one had cleared it. 23 passengers were killed and 176 injured in the collision.
• On 8 March 1965, a freight train derailed at Streatham Common. All four lines were blocked, closing the route between Balham and Selhurst.[14]
• On 16 December 1972, two electric multiple unit passenger trains collided at Copyhold Junction, West Sussex after the one of the drivers misread signals. Fifteen people were injured.[15]
• In the Purley station rail crash on 4 March 1989, an electric multiple unit passed a signal at danger and collided with another just north of Purley station. Part of the front train fell down the embankment, killing five people and injuring 88.