Four huge tunnel boring machines (TBMs) will dig the twin nine-kilometre tunnels. Like giant mechanical earth worms, they will chew through the rock and sand (silt) under Melbourne’s city centre.
Each one weighs 1000 tonnes (that’s about 150 elephants!).
Take a closer look
Check out the detail in our incredible cross-section which shows just how TBMs work.
TBMs work day and night. They dig 10 meters of tunnel a day and the tunnelling will take about 3 years in total. View the tunnel tracker, to see where our TBMs are under Melbourne right now
Hooked on TBMs? We are!
You can find more information with links to videos, images and fact sheets here.