Sydney Metro’s third mega tunnel boring machine (TBM) has started tunnelling, marking the next stage in delivering the new 31 km metro twin tunnels below the centre of Sydney and deep under Sydney Harbour.
TBM Wendy has started digging the 6.2 km of tunnel from Chatswood to the edge of Sydney Harbour at Blues Point. Wendy joins TBMs Nancy and Mum Shirl, the mega borers which launched last year and are now tunnelling from Marrickville towards the CBD.
With two more machines due to start work this year, the borers will build 31 km of Sydney Metro tunnels between Marrickville and Chatswood, including the first rail tunnels under Sydney Harbour.
The borers are underground tunnelling factories, mechanical worms designed to dig and line the tunnels as they go.
Wendy is one of five TBMs that will excavate 5.9 million tonnes of rock. TBMs Nancy and Mum Shirl have excavated 1.3 km of tunnel and 114,000 tonnes of crushed rock from Marrickville on the 8.1 km journey to Barangaroo.
The TBMs are about 150 metres long, or longer than two Airbus A380s, and specially designed for Sydney’s geology to cut through our hard sandstone.
Wendy and another TBM will tunnel towards the new Sydney Metro stations being constructed at Crows Nest and North Sydney before being retrieved at a temporary construction site at Blues Point.
A fifth machine has been specially designed to deliver the twin tunnels under Sydney Harbour.