Sorry for the delay

If it wasn't for the millennium, it wouldn't matter so much that the completion date for the Jubilee Line extension keeps being put back. But it's the vital link to the Dome - and the pressure on the project is beginning to tell

IN 1994, London Underground chiefs came close to mothballing its proposed new station at North Greenwich. Work was well underway on what was then a fairly insignificant stop on the Jubilee Line Extension, which was to run east from Green Park, taking in the major railway termini of Waterloo and London Bridge, along the Thames to the major new development at Canary Wharf, and then north to Stratford.

LU was having problems with British Gas, which owned large parts of the adjacent land, over its contribution to the costs of fitting out the station, and thought about putting it all on hold for a while. The station that really mattered was just over the river at Canary Wharf, with its massive new office developments. In comparison, North Greenwich was little more than a blob on the map.

How times change. Last week, London Underground announced it was offering exclusive rights to a single commercial sponsor for the opportunity to plaster its name all over North Greenwich Station. The price was a cool pounds 10m. "You could have `Cadbury's North Greenwich' or `Firestone North Greenwich'," said a spokesman for TDI, the company which handles Tube advertising. The deal would include laser displays and animated posters.

More significantly, the sponsor would have its name on the familiar London Underground bull's eye logo - the first time this has been allowed. Here was proof that North Greenwich is now the most important station on London's newest underground line, for one simple reason: the giant white marquee of the Millennium Dome, which stands close to its entrance.

More than 12 million visitors are expected to pitch up here in the year 2000, and 60 per cent of them will pass through North Greenwich station. It is no exaggeration to say that the station is crucial to the Dome's success. And this is the reason - rather than the fact it will provide better transport facilities for those who work in Docklands; will relieve road congestion; and will extend the Tube network to areas which it does not yet serve - which causes politicians so much anguish over continued delays to the Jubilee Line Extension (JLE). It was originally scheduled for completion in March this year, then the finishing date was extended to September. Now London Underground says the line will not open until next year. As yet, LU is not prepared to say exactly when the opening might take place, and some have doubts as to whether it will meet even a vague spring deadline. Two weeks ago, a cross-party Commons committee charged with overseeing the Millennium celebrations expressed the view that it still had "worries" that LU's assurances of a spring opening were "optimistic". Last week, LU announced it had hired the giant American engineering and construction firm Bechtel to give an "honest, independent appraisal" of the probability of meeting the target. Considering problems which have bedevilled the project since its inception, we could be forgiven for not holding our breath.

THE first setback occurred even before the first shovelful of earth had been lifted. In the early Nineties, the Thatcher government approved the scheme with the proviso that a percentage of the finance came from private funds. This was to have been provided by the Docklands developer Olympia & York, which had long pushed hard for just such a rapid transport link to be built. It agreed to pay pounds 400m over a period of several years, but when the first payment of pounds 40m was due in April 1992, as work was about to commence, the recession was hitting and Olympia & York found itself unable to meet the commitment. Six weeks later, the company went into administration. The government put a stop to the project and an 18-month delay followed as alternative funding was sought. In October 1993, agreement was finally reached for Canary Wharf Limited, the company which took over Olympia & York's responsibilities and is owned by a consortium of 11 banks, to pay an initial pounds 98m, with a further pounds 300m over a 25-year period after the line was opened. The ceremony to mark the beginning of construction was in December 1993, when John Major started the first pile-driver at the site of Canary Wharf station. Sir Wilfrid Newton, then chairman of London Transport, assured Mr Major that the extension would open "on time and on budget". Wrong on both counts, as it turned out.

"I must say, as I sit here and look back, I certainly didn't think we were going to have the problems we eventually had," says Hugh Doherty, JLE project director. "But when I think what we have achieved in that time, it's a hell of a lot. It was a highly ambitious project, a massive undertaking and very complicated technically." The size and location of the 10 miles of tunnelling were daunting in themselves. At the western end, huge excavations were required very close to and even underneath historic buildings. To the eastern end, water-bearing silts and sands meant conditions were unstable.

A decision had also been taken to use sophisticated software systems to run the trains. This was the only way to provide adequate capacity for increased passenger numbers in the years to come, and it had to be built from scratch. "We were at the cutting edge of technology," says Doherty. "We were leading the underground railway industry." Both the tunnelling and the software systems were to suffer unforeseen delays. In October 1994, nearly a mile of tunnelling had been completed when a tunnel constructed at Heathrow for the new express rail-link collapsed. The implications were serious - the Heathrow tunnel used the same sprayed- concrete technique as the JLE's. Work was halted while a painstaking review was undertaken to ensure a similar collapse would not happen. Delays ranged from six to 12 months on different parts of the project.

BUT by far the greatest delay has been caused by continuing problems with signalling equipment. A state-of-the-art bespoke system was ordered from Westinghouse Signals, which would allow the JLE to run up to 36 trains an hour, compared to an average of 17 to 24 on the existing network. The technology relied on what is known as a "moving block" safety system, which allows trains to talk to each other via radio beams and ensure a safe gap is maintained between them. But the equipment has been plagued with problems, to the extent that it has now been modified to operate on the older "fixed block" system, by which the track is divided into a series of sections with only one train allowed in any section at one time.

"Our focus is totally on the fixed block system to give us a proper railway by the spring of next year," says Doherty. At present, a single train is running on the line to allow the railway control systems to be tested. Doherty says the initial results are "very promising", but remains cautious of saying more "because obviously things come out of the woodwork". (It recently appeared that something extremely unpleasant had come out of the woodwork when the London Evening Standard reported that the new rolling-stock did not properly fit the rails on the old Jubilee Line, but the story was in fact untrue.)

Continuing delays have meant increased costs. Back in 1989, LU estimated the cost of the JLE at around pounds 1bn. By the time work commenced in 1993, the budget was pounds 2.1bn. By the time it is finally completed, it will have cost around pounds 2.8bn, and most of the cost of the over-run will have come from LU's development funds, which has led to serious neglect in other parts of the network.

One looming financial setback, however, appears to have been averted. Under the agreement with Canary Wharf Ltd, LU contracted to have the new line up and running by November of this year. Since it clearly will not be up and running by then, in theory LU will be liable for repayment of the initial pounds 98m. "We are in active dialogue with Canary Wharf to ensure that both parties come up with an acceptable formula," says Doherty. "We're reasonably hopeful we will not be beating each other up."

In construction terms, Canary Wharf has proved one of the two most problematic stations on the whole line. However, it is now forecast to be ready by Christmas, which means real concern now hovers only over Westminster. Doherty describes the challenge of building a new station at the site as "monumental".

The tunnelling at this point of the line is deeper than anywhere else on the network, and major precautions had to be implemented to ensure that Big Ben was not affected. According to Doherty, there is "a fair chance" that Westminster will not be ready in time for the deadline, but this will not prevent the line from opening. Trains will simply pass through the site without stopping.

And Hugh Doherty is confident that his 21st-century underground line will indeed open next spring, with or without a station at Westminster. A taste of what lies in store for commuters can be found 25 metres beneath the Greenwich Peninsula, where the cavernous North Greenwich station is complete but for the finishing touches. The walls and elliptical supporting columns are finished in dark blue mosaic, while down one side of the suspended concourse a long glass wall glows deep blue. From the platform, the curved, steel-clad underside of the concourse gives the impression of a ship's hull. It's unlike any other Tube station and will undoubtedly leave a lasting impression on all Dome visitors. Provided, of course, that the Dome is finished on time. But that's another story.

Engines, interchanges, escalators: the facts

l Nine of the 11 stations are interchanges, making the JLE the only Underground line to connect with all existing lines.

l Six stations are completely new to the underground system: Southwark, Bermondsey, Canada Water, Canary Wharf, North Greenwich and Canning Town.

l There's a new fleet of 59 six-car trains, each costing pounds 4 million and with capacity for 1,040 passengers. The first entered service on the existing Jubilee Line on Christmas Eve last year. All old stock on the Jubilee Line has now been replaced.

l The journey from Waterloo to North Greenwich, site of the Millennium Dome, will take 13 minutes.

l If the 244-metre Canary Wharf Tower was laid on its side, it would comfortably fit into the new Canary Wharf station, designed by Sir Norman Foster, which is 314 metres long.

l Canada Water station is roughly the size of St Paul's.

l Wherever possible, escalators have been built in threes rather than in pairs, so one is always on standby in case another breaks down. The 118 new escalators will increase the number of escalators on the entire Underground system by 50 per cent.

l All underground platforms have a glass safety barrier running along the edge. The doors in the barrier will only open when a train is safely stopped at a station.

l It is estimated that almost 50,000 person-years of employment have been created by the project.

l Archaeological discoveries made during the project included an early Roman settlement near London Bridge and a large mediaeval Cistercian abbey in Stratford, dating back to the 12th century.