Huge crane lifts Northern Line Extension tunnelling giants 20 metres below ground
Published: Thursday 16th February 17
A major milestone in the construction of the Northern Line Extension was reached this week with the lowering of two giant tunnel boring machines 20 metres below ground in Battersea, ahead of tunnelling starting in March.
The precision operation required a huge 750-tonne crane to lift the two tunnel boring machines, Helen and Amy, in the shadow of London’s iconic Battersea Power Station.
The Northern Line Extension helped to kick start the regeneration of Nine Elms and Vauxhall which is on course to create around 25,000 new jobs and more than 20,000 new homes. Construction is also boosting the UK economy, supporting around 1,000 jobs, including around 50 apprenticeships.
The two tunnel boring machines will create two 3.2km underground tunnels to extend the Charing Cross branch of the Northern line from Kennington to Battersea Power Station, via Nine Elms Station. Tunnelling will take six months to complete.
As well as two new tunnels, two new stations are being created: one at the heart of the Battersea Power Station redevelopment and another at Nine Elms to the east, serving new developments such as the US Embassy and the redevelopment of New Covent Garden Market, as well as existing communities.
The extension, targeted for completion in 2020, is the first major Tube line extension since the Jubilee line in the late 1990s.
Both tunnelling machines will now be fully assembled within two 77m long launch tunnels, before starting their journeys towards Kennington next month. When fully assembled, Helen and Amy will each be 100 metres in length.
Helen and Amy will excavate more than 300,000 tonnes of earth. This will then be passed along conveyors before being loaded on to barges and taken to Goshems Farm in East Tilbury, Essex, where it will be used to create arable farmland. This will remove more than 40,000 lorry journeys from the Capital’s roads, reducing congestion.
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