According to Victorian Premier Daniel Andrews, the cavern was excavated using three road headers, each of which can excavate roughly 500 tonnes of rock every day.
“The road headers have finished more than a years work under the city, digging 36 metres under Swanston Street, while also excavating the station length of 240 metres between Franklin and La Trobe Streets,” Mr. Andrews said.
“Later this year, they will go back underground to dig out the rail tunnels on each side of the central station cavern.”
Mr. Andrews said building works for the station are also underway, with a concrete floor installed that will form part of the future platform.
“State Library and Town Hall stations feature ‘trinocular caverns’ – three overlapping tunnels dug by road headers to create an open space for passengers, and allowing the concourse and platforms to be integrated on one level,” he said.
“State Library Station will be 240 metres long and 30 metres wide, and its 19-metre platforms will be some of the widest underground metro platforms in the world.”
The station will also include an underground passenger connection to Melbourne Central Station, so passengers can easily change between Metro Tunnel and City Loop train services.