The first of five TBMs is on its way to start boring on Australia’s biggest public transport project.
The 150m long TBMs will launch at Marrickville later this year and start tunnelling towards the new Waterloo Station - then under the Sydney central business district via new metro stations at Central, Pitt Street and Martin Place, before finishing at Barangaroo.
Altogether, the five TBMs will deliver new 15.5km twin metro railway tunnels from Chatswood to Sydenham, including under Sydney Harbour.
Taking six months to build, the double shield TBM will advance 1.7m each time and each cutterhead has 38 hardened steel cutters – weighing up to 400kg each – which will need to be replaced about every one-to-two weeks.
Two TBMs will dig about 8.1km from Marrickville to Barangaroo and two will cut about 6.2km from Chatswood to Blues Point. The fifth TBM has been specially designed to bore about 1km of tunnels under Sydney Harbour.
They are expected to tunnel about 120m a week on average.