Lea Valley Lines

The Lea Valley Lines are three commuter lines and two branches in North East London, so named because they run along the valley of the River Lea. They were operated for much of their history by the Great Eastern Railway.

History
The first section opened, by the Eastern Counties Railway (ECR) on 20 June 1839 from the London end at Devonshire Street to Romford, extended on 1 July 1840 to Bishopsgate (London end) and Brentwood. The Northern and Eastern Railway (N&ER) opened its first section from the above line at Stratford to Broxbourne on 15 September 1840, and to Harlow in 1841; though it remained a separate entity the N&ER's line was leased to the EC from 1 January 1844. A branch from Broxbourne to Hertford was opened in 1843.

Enfield was reached on 1 March 1849 by a single-line branch from the N&ER at Angel Road via Lower Edmonton. The ECR was incorporated into the Great Eastern Railway (GER) in 1862. A shorter route to Edmonton was eventually provided by the GER in 1872, from Bethnal Green via Hackney Downs and Stoke Newington, which section opened on 27 May; the section via Seven Sisters and Lower Edmonton, at a new high-level station provided adjacent to the old, low-level station, opened on 22 July. The line from there to Enfield was doubled at the same time. The section of the old line between Angel Road and Lower Edmonton was closed to regular passenger trains in 1939, except for occasional diversionary traffic including the period in the 1950s when the rest of the local network was being electrified; the line closed completely in 1964 and the rails removed soon after.

Another branch divided off eastwards north of Hackney Downs to Walthamstow in 1870, extended to Chingford in 1873.

The final section built linked Lower Edmonton on the Enfield branch via Churchbury (later Southbury) with the Broxbourne line, meeting the latter at Cheshunt, opening on 1 October 1891; it was generally known as the Churchbury loop until the renaming of that station in 1960.

Route and services
All lines start at London Liverpool Street or Stratford and are operated by Greater Anglia. The routes are:
 * Via Tottenham Hale. This line also forms the lower part of the West Anglia Main Line to Cambridge.
 * Via Seven Sisters. This line has a branch via Temple Mills at the southern end to Stratford, diverging just south of Seven Sisters. The line splits north of Edmonton Green with one short branch to Enfield Town and the Southbury Loop to Cheshunt, where it rejoins the Tottenham Hale line.
 * To Chingford.

Until 1970 the Tottenham Hale and Chingford lines were connected by a stretch of track called the Hall Farm Curve, which potentially may be reconstructed.

The line is part of the Network Rail Strategic Route 5, SRS 05.02, 05.04 and part of 05.01. It is classified as a London and South East Commuter line.

A minor service occurs running on from the Seven Sisters branch to Stratford via the Gospel Oak to Barking Line and the West Anglia Main Line. This is one of only two places on the Gospel Oak to Barking Line where it is electrified.

Infrastructure
The line is double track for most of its length, with some multitrack between Hackney Downs and Liverpool Street. It is electrified at 25 kV AC using overhead line equipment and a line speed of between 40-75 mph except between Cheshunt and Coppermill junction where the linespeed is 60-85 mph. Different sections of the line have different loading gauges. Most of the line is W8, with the branches to Enfield Town and Chingford being W6 and the branch to Stratford being W9.

Future developments
Following the completion of the Overground network in December 2012, TfL expressed its intention to operate several other suburban lines within the London area. In these proposals for railway services to be devolved to TfL included the West Anglian Suburban routes: Liverpool Street to Enfield, Chingford, Cheshunt and Hertford East.

In late June 2013, as part of the 2013 Spending Review, the Greater London Authority confirmed that Chancellor George Osborne gave the commitment for the Seven Sisters and Chingford lines of West Anglian Suburban Routes to be taken over by TfL by the end of 2015.

What these change will create from new investments and route options has not been officially communicated.