Two giant tunnel boring machines lowered into place for Northern Line Extension
... The tunnelling machines, named Helen and Amy, will create two 3.2km
underground tunnels which will extend the Charing Cross branch of the
Northern line from Kennington to Battersea Power Station, via Nine Elms
Station. Tunnelling work is estimated to take six months to complete.
The extension, targeted for completion in 2020, is the first major Tube
line extension since the Jubilee line in the late 1990s. ... According to Transport for London (TfL),
both 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