LONDON'S BID to host the 2012 Olympic and Paralympic Games received a boost last month with the start of work on the 2.5km Docklands Light Railway (DLR) extension to Woolwich Arsenal.
An earlier extension linking Canning Town to London City Airport, due to open in December, will initially terminate at King George V station at North Woolwich.
When finished early in 2009, the latest extension will continue the route under the Thames through two parallel bored tunnels to Woolwich Arsenal in south east London.
This will form an essential part of the Olympic transport strategy should London's bid be successful.
It will provide another DLR connection to the Olympic venue at Excel London in Docklands where the boxing, table tennis, taekwondo, weightlifting, wrestling and judo would be staged.
It will also interchange with the Greenwich Waterfront and East London transits and dedicated busways serving areas north and south of the River Thames.
Mayor of London Ken Livingstone said: 'This DLR route demonstrates to the International Olympic Committee that London is already delivering on its transport promises for the 2012 games.
'Simply bidding for the games has brought forward a host of transport improvements - with the East London Line extension, the new £400M ticket hall at King's Cross, and the £91M package of improvements to the North London Line all given added momentum.'
Amec is constructing the extension under a design and build contract for concessionare Woolwich Arsenal Rail Enterprises.
Special TBM on order Amec has ordered a custombuilt 6m diameter soft ground Lovat TBM for the Woolwich Arsenal extension.
The machine, which should arrive on site in November, will bore the 1.83km twin tunnels under the Thames. The crew will erect and install prefabricated concrete segments, forming an eight-piece, tapered trapezoidal ring, with a 5.8m outside diameter and an internal one of 5.3m.
The TBM uses variable frequency drives, a new Lovat feature, for soft-ground conditions.
It also features a screw conveyor with a peripheral drive mechanism for rear discharge to a muck pump. This will remove material for the 'rst 300m to 500m, before a switch to a continuous belt conveyor for the rest of the drive.
Geology along the tunnel alignment is expected to consist of terrace gravels, chalk and Thanet Sands.