Analysis
Tube modernisation.
LONDON Underground has completed the most visible aspect of its modernisation of the four sub-surface lines that run over, under and through the capital.
Passengers now travel in a fleet of 192 modern, air-conditioned trains of the same basic S-Stock design, built by Bombardier in Derby, instead of a mix of three different fleets (LU withdrew the final old trains, D-Stock, last April).
The four lines are the Metropolitan, Hammersmith and City, Circle and District Lines, hence the shorthand ‘4LM’ to describe their modernisation project. Between them, these lines carry 1.3 million passengers every day, which is around a quarter of London Underground’s daily ridership.
If the visible aspect is the trains, then the one unseen by passengers is the signalling, track layouts and depot changes. Remarkably, some trains still come under the control of signals and points operated from levers. These are miniature levers working power-operated points and colour-light signals.
The Metropolitan Railway installed a Westinghouse ‘K-Style’ lever frame in Edgware Road signal cabin in 1926. At the time, this was a major advance compared with the mechanical levers controlling signal and points on the wider rail network. Nearly a century later, the frame is a museum piece. Indeed, in 2016 the Railway Heritage Designation Advisory Board marked it as an item of national historic importance. Its role controlling trains will be taken in the next few years by computers with trains running under automatic control, albeit still with drivers in their cabs.
This upgrade has had a checkered history. Bombardier won the contract to supply new signalling in 2011, but made so little progress that Transport for London (TfL) terminated it in December 2013, saying there was little chance it would have delivered. Thales then won a revised £760 million resignalling deal in July 2015, having been the only bidder.
TfL expects the project to be complete in 2023, with 32 trains per hour (tph) running in central London and 28tph on the Metropolitan Line trunk from that May. This compares with between 22.5tph and 27tph running at the moment. Improvements will come in stages (see panel), as TfL and Thales commission new signalling that covers 15 distinct ‘signal migration areas’ (SMAs). The project is complicated by its size, its interfaces with Network Rail lines and signalling, and its interfaces with other LU lines.
By next autumn, TfL expects the new signalling to be controlling trains between Hammersmith and Euston Square. The first section will be Hammersmith to Edgware Road, and then between Edgware Road and Latimer Road (a section of line used by trains on the Circle and Hammersmith and City Lines). Last December, test trains ran on the Hammersmith and City Line ( RAIL 842), following similar tests last October. The first test of an S-Stock train under automatic train control took place at Neasden Depot on April 13 2017.
Following October’s tests, LU Managing Director Mark Wild said: “This is a fantastic step forward in the vital programme to modernise nearly half of the Tube network. The new signalling system will provide our customers with more frequent trains and quicker journeys, as well as improving reliability and improving customer information. We are making improvements for our customers all over the network, and this programme represents a hugely significant part of that work.”
Thales UK Transport VicePresident Shaun Jones said: “This is a significant milestone for us to achieve on this critical upgrade for London. We have demonstrated that our state-of-the-art radio communications technology will deliver better, more reliable journeys on 40% of the network, creating a world-class transport system for our capital city.”
The switch follows similar work on the Victoria, Northern and Jubilee Lines. Here modern, automatic signalling has enabled
TfL to increase service frequencies and cut running times to offer passengers more capacity.
The change was not easy at first, and TfL attracted criticism for delays in switching the Jubilee Line. Work started a decade ago, but it was not until 2011 that it was finished. This delayed equivalent work to the Northern Line. On the Victoria Line, in 2014 TfL introduced a service of 34tph. It now runs at up to 36tph.
TfL expects 130 of its S-Stock trains to be fitted with new signalling kit and 18 of its 29 engineering trains to be equipped by next autumn. The S-Stock trains will return to Bombardier in Derby to be fitted with the new kit.
By the same time, next autumn, TfL plans to have ten-car stabling sidings to be completed at Farringdon and Moorgate. They replace sidings removed a couple of years ago, and partially use the space once occupied by tracks that took British Rail diesel multiple units into Moorgate.
Farringdon is not the only location to have revised track layouts. According to TfL, Tower Hill’s new layout will make it easier to recover from disruption by allowing controllers to remove trains from service more quickly. Out on the Metropolitan Line, remodelling has brought higher running speeds and more reliable points. TfL is modifying 61 platforms to reduce the gap to trains.
Other locations include the vital junction station at Earl’s Court, as well as Mansion House and Putney Bridge. King’s Cross now has a new reversing siding.
A staff reorganisation is under way to cope with the shift from signal cabins to a single control centre at Hammersmith. TfL is recruiting control centre staff, signalling managers and technicians, and is training drivers.
None of this comes cheap. TfL estimates that the combination of new trains and new signalling will cost over £5 billion, split £2.2bn for signalling and £3.1bn for trains. By last summer it had spent just over £4bn.