The construction of two tunnel boring machines (TBMs) which will build the tunnels for the Northern Line Extension is now complete.
The 100 metres long machines were built by NFM Technologies in central France and will undergo factory testing before being dismantled and shipped to Battersea where they’ll be re-assembled.
Tunnelling is expected to start in early 2017 and will involve each machine undertaking two individual drives to construct the extension’s 5.2 metre diameter tunnels. As they advance, nearly 20,000 pre-cast concrete segments will be built in rings behind them.
Transport for London says the machines, which will be named by local school children, will run 24 hours a day, seven days a week and will stop only for scheduled maintenance.
As previously announced, spoil from the tunnelling work will be loaded on to barges and taken to Goshems Farm in East Tilbury where it’ll be used to raise former landfill sites to create arable farmland.
TfL claims this will avoid 40,000 lorry journeys which would otherwise add to congestion on the capital’s streets.
Mayor of London, Boris Johnson, said: “The construction of these mammoth machines is the clearest indicator yet that we are about to deliver the first major extension of the Tube in nearly 30 years.
“By extending the Northern Line we are improving access to the Tube for thousands of south Londoners as well as triggering the creation of vital new homes and jobs.”
Nick Brown, Managing Director of London Underground, added: “The TBMs will make their way to London later this year and in early 2017 will start powering their way under south London to create the first major Tube extension since the Jubilee line in the late 1990s.
“Their manufacture is a significant step forward in the project which, once complete, will help us to support jobs, homes and growth in this area and keep pace with London’s rapidly rising population.”