Crews working on Melbourne Metro have celebrated a milestone.

1 of 3 roadheaders digging Town Hall Station broke through to the station’s central cavern marking the completion of digging for its 3 entrances. Excavation of the station’s first level is now complete, 25 metres below Swanston St.

Roadheaders Lily, Sharon and Clara have been digging the station. Each one weighs 118 tonnes and is capable of smashing rock three times harder than concrete.

So far they have dug 42,000 m3 of rock & soil for the 240-metre long station.

They will continue to dig another 8 metres down for the station cavern with excavation expected to be completed in late 2020.