The first of eight giant tunnel boring machines (TBMs), which will carve out London's new Crossrail line, is in position, ready to start digging away under the capital on 21 March. The line, due for completion in 2018, will stretch from Maidenhead, Berkshire, through central London and split into two lines serving the East End.
The 1,000 tonne machine -- completed in December 2011 -- is now poised at its entrance "portal" in Royal Oak, west London. Between now and the start of the dig, Crossrail engineers will put the giant machine through final testing before it begins its 6.16km underground journey east to Farringdon, burrowing a tunnel that will link with Paddington, Bond Street and Tottenham Court Road stations.
Over the coming three years, a fleet of eight 150 metre-long TBMs (working in pairs) will begin several twin tunnels under the city, digging 21km of new subway. The longest, an 8.3km route, will extend westward from the Limmo Peninsula portal -- near Canning Town in the East End -- to meet the Farringdon tunnel.
Elsewhere, Heathrow airport will gain a tunnel link to the Crossrail line and another section will fork up to the Olympic site at Stratford from near Limehouse.
The enormous project prompted secretary of state for transport Justine Greening to comment: "It's exciting that we've reached this landmark for this world-class testament to our engineering excellence." Strong words.
Each of these epic machines, built by German manufacturer Herrenknecht AG, costs around £10 million. In fact, all of the figures involved in the project are suitably large: -- Each TBM, which will operate 24 hours a day, requiring a team of 20 people to function
-- 200 million people are expected to use the line every year
-- The Crossrail project has stimulated £250 million worth of contracts, involving more than 50 companies
-- The new route passes through some 37 stations of the London network
-- At its deepest point the new line will reach depths of around 40m
Still, they aren't fast: Each TBM will cover around 100 meters a week. That's approximately 0.0059524 km/h -- only 0.001km/h faster than a garden snail.
This article was originally published by WIRED UK
