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Tube Subsurface network (SSL) upgrade

£3.1bn will be spent on new trains and signalling for the Circle, District, Metropolitan and Hammersmith & City lines.


Metronet is in charge of the infrastructure and rolling stock of the District, Circle, Metropolitan, Hammersmith & City and East London lines, collectively known as the subsurface lines (SSL).

Under their Public Private Partnership (PPP) contract, they are obliged to meet certain performance targets, which rise as time passes. A series of infrastructure improvements, stock refurbishments and replacements and service alterations will be used to meet those goals.

In December 2006, it was announced that an additional option in the SSL contract would be taken, involving the extension of all Circle, District (Edgware Road - Wimbledon) and Hammersmith & City trains from 6 to 7 carriages to match the rest of the District line and the Metropolitan line. This will require platform lengthening work at 16 stations - minor work at 12 of these will begin in March 2008, with design works underway for major works at the remainder (including Baker Street). TfL press release, 6 Dec 06

2004+ - Track replacement

The first large track renewal project is on the District line between Earl's Court and Aldgate East. Train services on the District line between Earl's Court and Whitechapel were suspended along with the entire Circle line over about 25 weekends between mid 2004 and late 2005. In 2004, 2085m of track was replaced; in 2005 and 2006, similar work took place on the northern side of the Circle, between Baker Street and Liverpool Street (in parallel with works at King’s Cross).

2009+ - New trains

Impression of the exterior of new stock for the subsurface lines

A new uniform subsurface train stock of 190 trains will be delivered from 2009, starting with the Metropolitan line. The only difference between trains on different lines will be the lengths of the trains, making maintenance easier. (See mock images of the trains.)

Metropolitan line trains will be the same length as now, as will most District line trains (which will have shorter carriages but an extra one, resulting in the same train length). Trains on the Circle, Hammersmith & City and Edgware Road to Wimbledon service of the District line - which currently use the same "C-stock" - will be extended from six to seven carriages (each of equivalent length, resulting in a longer train).

The new trains will have interconnecting gangways allowing passengers to pass throughout the length of the train, which should help to solve overcrowding problems where one part of a train is full but another part has available seats.

The longer trains on the Circle, H&C and "Wimbleware" District services will require platform extension work at a number of stations currently only served by the shorter "C"-stock trains. In particular, major works will be required at Notting Hill Gate, Bayswater, Paddington (District/Circle) and Hammersmith (H&C).

The new trains will be air-conditioned, and their floors will be at the same height as the platforms, allowing step-free access onto the trains.

2011 - New service pattern

The peak hour service is currently 28tph on most of the subsurface network in Zone 1 and is due to be increased to 30tph, to be achieved by restructuring the service - in particular the Circle line.

Metropolitan trains would run through from Liverpool Street to Barking, and the Hammersmith & City service would run partially to Aldgate, and partially all the way around the Circle terminating at Edgware Road - i.e. Hammersmith - Edgware Road - Aldgate - Victoria - Edgware Road and reverse.

This is meant to give a period of recovery time which the Circle line currently lacks. Detailed information is available at Tubeprune's site and District Dave's site.

Works will be undertaken on the Hammersmith & City line station at Paddington to relieve overcrowding.

2014 - Signalling upgrade

By this time, the northern section should have received a signalling upgrade, including Automatic Train Operation (ATO). ATO is already in operation on the Central line and involves precise computer control of acceleration and braking (although the trains are not driverless). ATO results in faster journey times than possible with manual driving.

This should also mean an increase in frequency between Baker Street and Liverpool St from 30 to 34tph.

2017 - Full upgrade

By this time, the southern section of the Circle should also have received a signalling upgrade resulting in 34tph between Gloucester Road and Tower Hill.


(newest first)
Metronet infrastructure operator "bordering on disaster"
2005-04-06 12:04:39

TfL commissioner Bob Kiley told the London Assembly today that private infrastructure operator Metronet, which controls the subsurface lines (Circle, District, Metropolitan, Hammersmith & City and East London) as well three other lines, is "bordering on disaster", after over-running engineering works this morning meant that subsurface services in some cases started 75 minutes late, crippling the service for the rest of the day. Mr Kiley backed a Lib Dem proposal for TfL to immediately take Metronet's infrastructure functions back in house because of the poor performance.

Four-day or week-long closures mooted for maintenace
2004-03-26 08:37:48

Metronet have warned that they need more time to carry out essential maintenance on the ageing subsurface network, which could mean closing for four-day periods from Friday to Monday - but Simon Huges, the Lib Dem Mayor candidate, promotes week-long summer closures to make sure the work is complete.

Circle & District lines face weekend closures
2004-02-27 14:11:41

According to the Evening Standard, TfL have announced that the District and Circle lines will close at weekends between Tower Hill and Earl's Court for 17 weekends - much like the recent Baker Street to Liverpool Street closures in connection with the King's Cross rebuild.

Links & Sources

  1. Tubeprune: SSL Upgrade
  2. District Dave: SSL Upgrade
  3. Metronet

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