Friday, 11 May 2012

Anglia relief line

London's rail network is in many places absolutely full, yet there is still a need for capacity growth of 40 to 50% in the next 20 years. One of the most congested areas is the north-east segment of the London area - the Anglia lines - and this blog looks at a possible radical intervention.

Anglia lines of north-east London

The Anglia lines form are those mainline rail services into and out of Liverpool Street. These naturally form 4 sub-groups of services:

  • Great Eastern slows - all-station services via Ilford and Romford
  • Great Eastern fasts - fast services to Shenfield and beyond, including Chelmsford, Colchester and Southend Victoria
  • West Anglia slows - all-station services via Hackney Downs, Seven Sisters and Tottenham Hale
  • West Anglia fasts - fast services to Harlow and beyond, including Cambridge and Stanstead Airport, although Hertford East could be included in this group

The infrastructure currently has 4 tracks on the Great Eastern route - 2 tracks for slow and 2 tracks for fast. On the West Anglia route, there are 4 tracks between Bethnal Green and Hackney Downs, but there are only 2 tracks via each of Seven Sisters and Tottenham Hale, with Tottenham Hale being the faster route. There are only 6 tracks on the entry to Liverpool Street station as well, which tend to be allocated as 4 tracks for Great Eastern and 2 tracks for West Anglia. There is also a 2 track section from Tottenham Hale direct to Stratford.

There is current investment in the area through Crossrail. This is intended to take most of the Great Eastern slows away from Liverpool Street and into the new tunnel. Unfortunately, there is not enough capacity on Crossrail (due to the eastern branch problem) to remove all Great Eastern slows in the rush hour, thus it is intended that a "residual" service of 6tph (trains per hour) will still run into Liverpool Street.

There is also a potential plan to widen the section from Tottenham Hale to Brimsdown on the West Anglia route. This would be used to run more slow services on that route, but only to Stratford (not Liverpool Street) via the direct route from Tottenham Hale to Stratford.

The problem is that the Crossrail and Tottenham Hale investments are not really sufficient to fix the capacity problems of the area. The main problem is with the fast services, although the slow West Anglia services also have issues.

On the Great Eastern route, the fast services are at 24tph today and the London and South East RUS (the official document examining capacity constraints) suggests that any further increase in number of trains is difficult. The issue is that the 2 fast tracks from Liverpool Street serve 2 branches beyond Shenfield - the main line to Norwich via Chelmsford, Colchester and Ipswich, and the line to Southend Victoria (with London Southend airport). The effect of taking trains from 2 busy lines and merging them into 1 pair of tracks is congestion - trains often crawl through the junction at Shenfield.

On the West Anglia route, the fast services have to run on the same tracks as the slow services. This greatly reduces the frequency of the slows, something which the potential 4 tracking of Tottenham Hale to Brimsdown would help with. The fast services are also not especially quick, which is significant to Stanstead Airport, with its long 45 minute journey time to London.

When looking at the problems and constraints, it seems like a radical solution may be necessary.

Anglia Relief line

The Anglia relief line is an outline approach to the capacity problems in the area, detailed here as a high level proposal. The key aim is to produce a single scheme with widespread benefits to boost the business case.

The core of the Anglia Relief line is to recognise the need for a new fast line to serve the area. This is vital, as the 2 fast Great Eastern tracks are full. London is heavily built up, so adding a 2 new tracks obviously requires a tunnel. When looking at the problems of both West Anglia and Great Eastern together, one route made sense.

The Anglia Relief line is thus proposed to be a tunnel from Stratford to a location alongside the M11. From there, the line would continue beside the M11 with either a branch or routing via Epping. After Epping the line would split - 2 tracks to reach the West Anglia route east of Harlow and 2 tracks to reach the Great Eastern route south of Chelmsford. The junctions at Epping and Harlow east would be triangles to enable flexible routing (Chelmsford south could also be a triangle, but that would be mostly for freight to go from east London to Cambridge and the north). New stations would serve Chipping Ongar and Harlow South.

This new line would allow a recast of services:

  • Most West Anglia fasts from Stansted/Cambridge would be diverted via the new line (faster journey time)
  • Some Great Eastern fasts from Chelmsford would be diverted via the new line (assuming comparable journey time)
  • More Southend services could be run on the Great Eastern route via Romford
  • More slow and semi-fast services could be run on the West Anglia route via Broxbourne
  • A fast service can be added to Epping, relieving the Central line
  • Direct service from Colchester and Chelmsford to Stansted

One conceivable timetable would be:

  • 6tph first stop Epping with 3tph continuing to Harlow and 3tph to Chelmsford
  • 4tph Stansted Express (not stopping at Epping)
  • 4tph West Anglia fasts to Cambridge and beyond (not stopping at Epping)
  • 6tph Great Eastern fasts to Chelmsford and beyond (not stopping at Epping)
  • 3tph Colchester and Chelmsford to Stansted

(This timetable is an initial guess. It may be that there need to be more West Anglia fasts, or more Great Eastern fasts, or there isn't room for the Epping slows, more detailed work would need to establish that.)

However, the big issue with the scheme isn't the routing or the potential service gains, it is the perennial problem of where the trains can go once they reach London. Liverpool Street is pretty full. Broadgate is an office development. Shoreditch will soon be an office development. Stratford has been built over without thought of further rail expansion. All in all, a big problem.

I'm open to suggestions on this aspect. Perhaps the Anglia Relief line would have to link to a new tunnelled line through London, possibly Stratford - Canary Wharf - Lewisham - Brighton Main line (as opposed to through the zone 1 core).


This proposal outlines a concept proposal to route a relief line to both West Anglia and Great Eastern via a tunnel and alongside the M11, with a raft of benefits. However, the biggest problem is not the scheme itself, but where the trains go when they arrive in London.

If you think the concept proposal has merit, or have any other opinions, why not leave a comment!