Tunnel boring machine (TBM) Kathleen is digging twin railway tunnels under Sydney Harbour as part of the Sydney Metro project.
The specialised TBM is named after Kathleen Butler, who played a vital role in the construction of the Sydney Harbour Bridge, as technical adviser to engineer John Bradfield.
Metro trains will start to run through the tunnels once the project is completed in 2024. This will extend the North West Metro into the city and beyond to Bankstown.
Sydney Metro will have the capacity of a train every two minutes in each direction under the Sydney CBD. It will be able to move more people across the harbour during peak hours than the Harbour Bridge and Harbour Tunnel combined.
“This is an engineering feat of historic proportions for our great city which will forever change how we get around Sydney,” Premier Gladys Berejiklian said.