Contractor Amec last month used a 1000t crane to lower a 540t tunnel boring machine into a launch pit in North Woolwich, east London. It will then begin a 15-month journey 35m under the River Thames.
The machine will bore two 5.3m diameter tunnels as part of the £180M, 2.5km extension of the Docklands Light Railway to South Woolwich.
The TBM will travel through the Thames Gravels under North Woolwich, head south through chalk strata and then climb up through the Thanet Sands, resurfacing south of the river in South Woolwich.
It will then be taken back across the river before excavating the second parallel tunnel. Travelling at 2m an hour, it will remove a total of 104,000m3 of material.
Drilling begins this month with completion of the first leg expected in September.