Brighton Main Line

The Brighton Main Line is a British railway line from London Victoria and London Bridge to Brighton. It is about 50 miles (80 km) long, and is electrified throughout. Trains are operated by Southern, First Capital Connect, and Gatwick Express, now part of Southern.

Original proposals
There were no fewer than 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, for the most direct of these alternative routes. The scheme was to build a line from a junction with the London and Croydon Railway (L&CR) at Norwood to Brighton. The existing L&CR route from Norwood to London Bridge would also be used. One complication however, insisted on by the UK Parliament, was that the new railway should share its line between Croydon and Redhill with the South Eastern Railway main line to Dover. This clause in the act gave rise to sixty years of disputes between the two companies concerned.

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

Due to the difficult terrain and relatively limited 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 at Merstham, with one of the largest cuttings in Britain; seven tunnels (Merstham, Quarry, Redhill, Balcombe, Haywards Heath, Patcham and Clayton); and several embankments. There is also the 1,475 ft, 96 ft Ouse Valley Viaduct near Balcombe.

The line was opened in two stages:
 * 12 July 1841: Norwood Junction, London (L&CR) to Haywards Heath.
 * 21 September 1841: the final section from Haywards Heath to Brighton.

Branch lines
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 for the line having arrived by sea). 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).

Lines to Victoria
A branch line from Norwood to the resited 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 Croydon and Balham was opened in 1862.

Quarry line
There were frequent disputes resulting from the two companies' sharing of the busy section between Croydon and Redhill. The LB&SCR owned that section between Croydon and Coulsdon North, and the SER (later the South Eastern and Chatham Railway from Coulsdon to Redhill. Eventually the LB&SCR built an avoiding line between Coulsdon North and Earlswood which became known as the Quarry Line, and which is still used by fast trains avoiding Redhill. It was opened on 8 November 1899 (1 April 1900 for passenger traffic).

Electrification
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, and in 1920, that from London Bridge to South Croydon. In 1921 plans were drawn up to extend overhead electrification to Brighton. However, the 1923 grouping intervened and it only ever reached Coulsdon North, before the Southern Railway decided to standardise using the third-rail system of the former London and South Western Railway. Thus in 1928/29 the existing lines were converted to third-rail operation.

The decision to electrify the entire main line was taken in 1929, and the section from Coulsdon North – Three Bridges was opened in July 1932. That from Three Bridges – Brighton (and also to West Worthing) was operational from 1 January 1933.

The third-rail system is electrified at 750V DC and in recent years had its power supply upgraded ready for the introduction of new Electrostar stock operated by Southern. Traction current supply for the whole route is overseen by Lewisham, Selhurst and Brighton electrical control rooms.

Services


There are now many more trains from Victoria to Brighton than from London Bridge: a reversal of the original pattern. The line is four-tracked as far as Balcombe Tunnel junction, where it becomes a single pair through to Preston Park station. With the exception of a pair of platform loop lines at Haywards Heath station there are no passing places.

The fastest services from Brighton to Victoria call only at East Croydon and Clapham Junction, though some "express" services also call at Gatwick Airport. First Capital Connect services from Brighton to London Bridge continue via the Thameslink route across London to Blackfriars, City Thameslink, Farringdon and St Pancras, and then on to Luton and Bedford.

The Gatwick Express also uses the Brighton Mainline, with non-stop services running between London Victoria and Gatwick Airport. A train departs in both directions every 15 minutes, with a journey time of 30 minutes. Six weekday peak-hour Gatwick Express trains are extended to or from Brighton, up to London in the morning (calling at up to five other stations along the way) and down to Brighton in the evening.

Contingency options
From Balcombe Tunnel junction southwards to Preston Park station the tracks reduce from two pairs of running lines to one pair. Any train which failed in this section would cause major disruption, so two provisions are in place to keep the service running.

Bi-directional signalling
The line is divided into three sections of bi-directional signalling, which allows trains to cross over to the opposite line and run in the "wrong direction". These are:


 * Balcombe Tunnel junction to Copyhold Junction (just north of Haywards Heath station).
 * Haywards Heath to Keymer junction (just south of Wivelsfield station).
 * Keymer junction to Preston Park station.

Diversionary route
The section from Wivelsfield to Preston Park can be bypassed by turning eastwards on to the Lewes line at Keymer Junction. Once at Lewes, a reversing move is made and the train returns westwards to Brighton via the East Branch line, rejoining the main line at Montpelier Junction. This prevents the train from calling at Burgess Hill, Hassocks, and Preston Park.

Branching routes


From Victoria, the following other services use the line, but branch off where shown:
 * at Battersea Park, the South London Line to London Bridge
 * at Balham, where the line via Crystal Palace diverges
 * at South Croydon, the Oxted Line
 * at Purley, the Caterham and Tattenham Corner Lines
 * at Redhill, the branch to Reigate and the North Downs Line to the west; and the Tonbridge line to the east
 * at Three Bridges, the Arun Valley Line services to Portsmouth and Horsham; here was also a line to East Grinstead, closed in 1967
 * at Haywards Heath, the line via Ardingly and Horsted Keynes, closed in 1963: Currently Network Rail Sidings to Ardingly only; Horsted Keynes section is now part of the Bluebell Railway
 * at Wivelsfield (Keymer Junction), the East Coastway Line to Eastbourne and Hastings via Lewes
 * at Preston Park, the West Coastway Line service to Littlehampton, avoiding Brighton
 * at Brighton, the West Coastway Line; and the East Coastway Line to Eastbourne and Hastings and also to Seaford all via Falmer