Your browser is no longer supported

For the best possible experience using our website we recommend you upgrade to the newest version of your browser.

Your browser appears to have cookies disabled. For the best experience of Construction News, please enable cookies in your browser.

Welcome to the Construction News site. As we have relaunched, you will have to sign in once now and agree for us to use cookies, so you won't need to log in each time you visit our site.
Learn more

Why Metronet Rail blocked the Drain

SITE REPORT

No one is sure where London Underground's Waterloo and City line got its nickname. But the clues are there. It's dark, it's a bit smelly and there are rats, as Joanna Booth found out when she went down The Drain to see what work Metronet will carry out during its . ve-month closure, which began on Saturday

THE WATERLOO and City line is in a poor state of disrepair. 'It needs a lot of work, ' admits Jack Carter, programme manager for Metronet Rail.

Though he is keen to emphasise that the line complies with London Underground safety standards, Mr Car ter reveals that sect ions of it receive only an 'E' grading, the worst rating that Metronet gives for the condition of assets.

The line belonged to British Rail until 1994, when it was bought by London Underground for the grand sum of £1. 'It hadn't been maintained to LUL standards, ' Mr Carter says.

Running underneath the Thames, the tunnel is cold and has problems with damp, despite piles of ballast shifting underfoot. Some of the timber sleepers are so ancient that they were installed using the old-fashioned method of runn ing in line with the track, rather than at right angles to it. The curve of the walls sends strange echoes bouncing down the track.

Sequences for the film Harry Potter And The Philosopher's Stone were filmed here in 2000.

'It's a nice walk, ' Mr Carter says. 'You can do the whole length in an engineering shift. You can hear the sound of boats' engines passing overhead.' But the track is in poor condition, which has resulted in some speed restrictions being placed on trains running through it. The rolling stock also needs refurbishment and the existing signalling system cannot cope with all five of the dedicated trains running at any one time, limiting the service. As it is a main artery for workers coming into the financial heart of London the pressu re is on to improve.

'Metronet borrowed a lot of money from the City to enable it to undertake the Public-Private Partnership. I think the City feels it now owns this line, ' Mr Carter jokes. Over the five months from April to September of this year Met ronet is overseeing £40 million-worth of works inside the tunnel under its 30-year PPP contract with London Underground. The activities will continue 24 hours a day, 7 days a week, with 240 staff working in three shifts.

First the team needed to ensure they could see what was wrong. Now, the insides of the tunnel are illuminated, showing the marks of wooden shuttering in the concrete lining, which has been in place since the 1890s. This wasn't always evident.

'When I first walked the tunnel the only light we had was from our head torches, ' Mr Carter recalls.

'One of our first jobs was to get decent lighting in.'

Now lights, a leaky feeder for radio communications and electrical and air cables have been fitted to the tunnel length, ready for works to start the minute the possession begins.

Detailed surveys were undertaken of the entire 2.37 km leng th of the tunnel. It is unique among London's tube tunnels in being completely underground, ending in a brick wall at Bank station and a depot at Waterloo beneath the mainline station. The 3.7 m-wide tunnel has some particularly tight curves.

'There is lit tle run-in to the bends, they just come off straight sections, ' Mr Carter explains. 'Our design pinches out as much as possible from the tunnel to achieve smoother curves.' The line, which transports 9.6 million commuters a year in and out of the heart of the City of London, is getting the works. All sleepers and rail will be removed and completely re-layed, a new drainage system will be installed, the signalling and service control systems will be modernised and the entire f leet of trains refurbished. The extent of the works meant that a full line closure was necessary.

'Previously all the works were scheduled under separate projects to be done in 87 weekend closures plus others ranging from four to 30 days ? it was horribly inefficient, ' Mr Carter remembers.

In September last year London Underground agreed to a five-month closure. Balfour Beatty Rail's London Underground managing director Richard Adams likens the process to ripping a sticking plaster off the skin rather than peeling it slowly.

'It's much less painful in the long term. With the scope of works as they are I'm not sure it would even have been possible to do them in short possessions.' Works during the closure are being governed by a new set of health and safety standards tailor-made for the project (see right).

The first two weekends after the closure will see the road outside the Waterloo depot closed, the shaft roof removed and the rolling stock lifted out by a 500-tonne mobile crane. These trains are the pit-ponies of the Underground, not having seen light since they were lowered into the tunnel in 1993. The 20 carriages will be taken on trailers to Doncaster for refurbishment.

Four purpose-built battery locomotives with trailers will be craned in to transport materials. The track will be removed and sleepers broken out. Drainage shingle will be dug out and power rails removed.

A d rainage channel will be formed to take water to the pumping station at a mid-point under the Thames.

Concrete sleepers will be installed every metre ? at half that distance around bends ? and 113 lb rail installed. A new relay-based signal system will be designed and building alterations made for a control room, driver's facility, depot and manager's office.

The platforms at both Bank and Waterloo will receive a much-needed deep clean. All works bar rolling stock refurbishment and installation of a centralised control system are being undertaken by Balfour Beatty Rail.

'Logistics are a big part of this job, ' says Mr Adams. 'There are only two access points to the site, very lit tle storage, and incredibly busy roads with little parking space around the site at ground level.' Materials will be delivered via an access road under Waterloo station into the depot and sidings area, lowered and moved by overhead gantry cranes.

New rail will be lowered down the train shaft, through which spoil will also be removed.

The 240 operat ives employed on the site will be a mixture of highly-skilled Balfour Beatty staff, drafted in from their current work at Heathrow's Terminal 5, and framework subcontractors. There will be four separate teams working on rip-out, rebuild, materials and safety management.

'We're encouraging workers to commute using public transport, ' Mr Adams explains. 'Any parking space we've been able to secure around the station will be needed for off loading materials.' When works are complete London Underground estimates it can shave 50 seconds off journey times and run 25 per cent more trains, flushing commuters down The Drain at even greater rates than before.

WATERLOO AND CITY AT A GLANCE

Opened in 1898, it was the second deep line tube tunnel to be built in London

Hand-dug and lined with iron rings covered in concrete

2.37 km long and 3.7 m wide

3,806 tonnes of spoil, 2,515 timber sleepers and 9,000 m of old rail will be removed

5, 650 new sleepers and over 10,000 m of rail will be installed, plus 4,450 m of third rail

The project will use 1,630 tonnes of premixed concrete in 65,000 bags