Crossrail’s chief executive said tunnelling work was just nine months away as a German manufacturer was chosen to deliver six tunnel boring machines for the £15.9 billion project.
Crossrail’s tunnelling contractors selected Herrenknecht AG to deliver the first six machines required for the new rail tunnels.
The German tunnelling specialists will deliver two TBMs to Royal Oak Portal for the western running tunnels in early 2012, two TBMs to Limmo Peninsula for the eastern running tunnels in mid 2012, and a further two machines to Stepney Green later in 2012.
To construct the 21 km of twin-bored tunnel required for Crossrail, at least seven tunnel boring machines will be required and will undertake 10 individual tunnel drives to construct the 6 m diameter rail tunnels.
The TBMs required for Crossrail will be up to 120 m in length and weigh about 850 tonnes.
Crossrail chief executive Rob Holden said: “In less than a year, the first tunnel boring machines will have arrived and begun their journey from Royal Oak to Farringdon.
“Even though the start of tunnelling is still about nine months away, work has been ongoing since early 2010 to construct the tunnel portal at Royal Oak from where the first TBM will launch.”
The six TBMs will be transported to London by boat from the manufacturer’s factory in Schwanau, Germany.
The specific points of arrival in the UK are yet to be agreed between the manufacturer and the tunnelling contractors. Before they depart for the UK they will be fully assembled and tested before being dismantled into sections ready for transport.
Londoners will be given the chance to name the tunnel boring machines and will be able to follow their progress as they make their way under the capital via the Crossrail website.
Mayor of London Boris Johnson said: “There is nothing boring about the leviathan machines that will soon be burrowing their way through the earth way below our streets.
“These monsters of the deep will create the tunnels that will make it easier for millions of people to whizz east to west across our city.”
As the TBMs advance, precast concrete segments will be built in rings behind them.
Crossrail also confirmed that the concrete segments for the western running tunnels between Royal Oak and Farringdon would be manufactured at Old Oak Common and transported to the TBM by rail.