Around 150 metres in length, each TBMs is longer than two Airbus A380 aircraft and designed to cut through Sydney’s hard sandstone.
Two TBMs will tunnel 8.1 kilometres from Marrickville to the city. Another two will dig the 6.2 kilometres from Chatswood to the edge of Sydney Harbour. A specifically designed fifth machine will dig the twin tunnels under Sydney Harbour.
The TBMs will dig an average of 120 metres per week.
Premier Gladys Berejiklian said the Sydney Metro will transform Sydney’s public transport and give people greater choice in how they get around Sydney.
“Today marks the start of the huge task of digging twin tunnels under the city, delivering Sydney’s new world-class metro railway and building a stronger, better future for the people of NSW,” Ms Berejiklian said.
One of the TBMs is named Nancy after Nancy Bird Walton OBE, a pioneering Australian aviator. Walton was the first female pilot in the Commonwealth to carry passengers, helped set up the Royal Flying Doctors and trained female pilots during World War Two.