Four Lines Modernisation
The Four Lines Modernisation (4LM) is a series of projects by Transport for London to modernise and upgrade the sub-surface lines of the London Underground: the Circle, District, Hammersmith & City and Metropolitan lines.
The upgrades entail new rolling stock, new signalling and new track and drainage [1]
Rolling stock
As part of the upgrade, the entire sub-surface fleet was to be replaced. S7 and S8 Stock manufactured by Bombardier Transportation's Derby Litchurch Lane Works were ordered to replace a variety of rolling stock, these being the A60/62 Stock on the Metropolitan line, the C69/77 Stock on the Circle, District (Edgware Road to Wimbledon section) and Hammersmith & City lines, and the D78 Stock on the District line, which all dated from the 1960s and 1970s.
The order was for a total of 192 trains (1,403 cars), and formed of two types, S7 Stock for the Circle, District and Hammersmith & City lines and S8 Stock for the Metropolitan line. The main differences, aside from the number of cars (S7 having 7 cars and the S8 having 8 cars), were in the seating arrangements, in which the S7 Stock comprised of a longitudinal-only layout, whereas the S8 Stock had a mixture of longitudinal and transverse seating. New features that were not used on the previous rolling stocks included air-conditioning, low floors to ease accessibility, and open gangways between carriages.[2][3]
The entire fleet was introduced by April 2017.
| Line | Stock | First Unit Introduced | Fully Introduced |
|---|---|---|---|
| Circle | S7 | 2 September 2013 | 11 February 2014 |
| District | S7 | 2 September 2013 | 21 April 2017 |
| Hammersmith & City | S7 | 6 July 2012 | 11 February 2014 |
| Metropolitan | S8 | 31 July 2010 | 26 September 2012 |
Signalling
Part of the modernisation includes the introduction of Communications-Based Train Control (CBTC) to allow for Automatic Train Operation (ATO). In order to upgrade the signalling, Signal Migration Areas have been created to allow for the gradual installation.[4] Below is a list of the SMAs and their progress:
| SMA | From | To | Line(s) | Status | Date |
|---|---|---|---|---|---|
| 0.5 | Hammersmith | Latimer Road | Circle and Hammersmith & City | Completed | March 2019 |
| 1 | Latimer Road | Paddington | Circle and Hammersmith & City | Completed | September 2019 |
| 2 | Paddington & Finchley Road | Euston Square | Circle, Hammersmith & City and Metropolitan | Completed | September 2019 |
| 3 | Euston Square | Monument & Stepney Green | Circle, District, Hammersmith & City and Metropolitan | Completed | March 2021 |
| 4 | Monument | Sloane Square | Circle & District | Completed | April 2021 |
| 5 | Sloane Square | Barons Court, Fulham Broadway,
Olympia & Paddington |
Circle and District | Completed | March 2022 |
| 6 | Stepney Green | Becontree | District and Hammersmith & City | Planned | October 2022 |
| 7 | Becontree | Upminster | District | Planned | 2023 (TBD) |
| 8 | Finchley Road | Preston Road | Metropolitan | Planned | March 2022 (TBC) |
| 9 | Preston Road |
|
Metropolitan | Planned | September 2022 (TBC) |
| 10* | Barons Court |
|
District | Planned | TBD |
| 11* | Stamford Brook | Richmond & Ealing Broadway | District | Deferred | Until further notice |
| 12* | Fulham Broadway | East Putney | District | Planned | TBD |
| 13 | Moor Park |
|
Metropolitan | Planned | February 2023 (TBC) |
| 14 | West Harrow | Uxbridge | Metropolitan | Deferred | April 2023 (TBC) |
As a result of the first 5 SMAs being installed, the Circle line now runs entirely under ATO.
Originally the SMAs were planned as follows:[4]
| SMA | From | To | Line(s) |
|---|---|---|---|
| 10 | Barons Court | Richmond & Chiswick Park | District |
| 11 | Chiswick Park | Ealing Broadway | District |
| 12 | Fulham Broadway | Wimbledon | District |
For various reasons including funding and the technical difficulties with sharing tracks with National Rail & the Piccadilly line, SMAs 10-12 were scaled back until further notice.
References
- ^ "Four Lines Modernisation". Transport for London. Retrieved 2022-05-11.
- ^ "SQUAREWHEELS.org.uk – S stock". www.squarewheels.org.uk. Retrieved 2022-05-11.
- ^ "S7/8 stock - Tube History". tube-history.uk. Retrieved 2022-05-11.
- ^ a b "Programmes and Investment Committee - Four Lines Modernisation Update" (PDF). Transport for London. 13 October 2017. Retrieved 24 July 2022.
External links
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