Two giant tunnel boring machines have been carefully lowered into the depths of subterranean Battersea ahead of tunnelling begins on the Northern line extension in March. The extension will create new tunnels from Kennington to Battersea Power Station, giving Charing Cross branch trains a new terminus.
The project will also create two new stations, one at Battersea Power Station and the other at Nine Elms. To make this happen, two 3.2km underground tunnels need to be created.
The two boring machines are called Helen and Amy respectively, names which were chosen by local school children. They're named after the first British astronaut, Helen Sharman, and British aviation pioneer Amy Johnson, who was the first female pilot to fly solo from Britain to Australia.
Helen and Amy had to be lowered by a 750 tonne crane, and will now be fully assembled 20 metres below ground. Tunnelling will take six months to complete, but the extension isn't planned for completion until 2020.
The machines will excavate over 300,000 tonnes of earth, which will then be sent down the Thames to Goshems Farm in East Tilbury, where it will be used to create arable farmland.