London Jubilee Line Extension, United Kingdom

The development of London Underground's Jubilee Line from Green Park, through South London and Docklands to Stratford, has proven to be a troublesome project. The original target of Spring 1998 for opening the extension was not met, largely due to problems with tunnelling on the first phase, which cuts under some of the busiest parts of the English capital. Westminster and Southwark stations, the final parts of the project, were not opened until December 1999.

The Jubilee Line was expected to set the pattern for future investment in the network, with increasing involvement of private finance.

JUBILEE LINE PROJECT

Costing £3.5 billion, the project had been expected to take just under three years to complete. In opening the new route, the original Jubilee line of 1979 was diverted from its terminus at Charing Cross, with the new line running from Green Park to Westminster, Waterloo and on eastwards to a new terminus at Stratford.

The route serves the growing business and media communities around Canary Wharf and London Docklands, while nearby, at North Greenwich, the largest station on the new section has been built to serve the Millennium Dome attraction.

UNDERGROUND INFRASTRUCTURE IMPROVEMENTS

The extension is 10 miles (16km) long, of which 7.7 miles (12.4km) is in tunnel and 2.3 miles (3.5km) on the surface. Infrastructure improvements on the existing route give a potential capacity for 27 trains per hour, seven more than the original scheduled peak service.

Some technical problems were encountered with the tunnelling, but the largest incident to affect progress was not on the Jubilee Line itself, but was the collapse of a tunnel during work on the extension of the Piccadilly Line to Heathrow Airport's terminal 4. This led to a temporary halt in work and the modernisation of tunnels at Waterloo and London Bridge, raising the overall forecast cost by £190 million.

The stretch at the eastern end of the line, between Canning Town and Stratford, is the longest section not in tunnel. However, in the double-deck Canning Town station, and the vast complex at Stratford Market where the extension's new train fleet will be based and maintained, it boasts two of the most distinctive buildings of the whole project.

This section also boasts some very busy interchanges. At Stratford, for example, the line intersects with the Docklands Light Railway, LU's Central Line, and heavy rail routes from East Anglia and east London into Liverpool Street, and the North London Line.

EXTRUDED ALUMINIUM TRAINS

The line is operated by 59 new six-car trains built by Alstom in Birmingham. The bodyshells are built of extruded aluminium which is very strong yet comparatively light.

The weight of the rolling stock is kept down further by the use of AC rather than DC motors (this is also expected to make maintenance easier). The trains are equipped for automatic train control (ATC) operation, with a maximum design speed of 100km/h (60mph).

MOVING BLOCK SIGNALLING

New signalling, power and communication systems have been installed, and existing tunnels adapted to allow them to cope with the new generation of trains. Some track and platform realignment has been carried out.

However, plans to install a moving block signalling system on the new portions of the route were put on hold when doubts arose over whether it could be implemented in time for the first trains. However, a moving block system remains an option for the future.

The extra trains will be particularly welcome over the central section of the existing route, between Swiss Cottage and Baker Street, which is one of the 20 busiest sections of line of the Underground network, with trains running with an average of 25% more passengers than their theoretical capacity.

THE FUTURE OF THE JUBILEE LINE

The expanded line opened in early 2000, just in time for it to help meet the expected extra demand created by the Millennium Dome. That the Dome struggled to meet its attendance targets has been in no way due to the lack of a new, efficient and quick link into London's underground system.