Breakthrough at new Town Hall Station
Workers have excavated deep under Swanston Street to create a space longer than a city block and as deep as a five-storey building for the Metro Tunnel project’s new Town Hall Station.
A huge excavating machine known as a roadheader broke into the central cavern, where another two roadheaders have been excavating the station and three underground passenger walkways with entrances at Federation Square, City Square and Flinders Quarter.
More than 42,000 cubic metres of soil and rock has been dug by the roadheaders – enough to fill 17 Olympic swimming pools – with the machines set to dig another eight metres down to the final depth of around 33 metres.
After being launched late last year from an access shaft at City Square, the first roadheader tunnelled directly under Swanston Street to begin excavating the main station cavern.
A second roadheader was launched under Federation Square and has been digging to create an underground passenger connection across Flinders Street and under Swanston Street to the station site.
A third roadheader has been working to create the underground passenger connection from Flinders Quarter – alongside the Young and Jackson Hotel – across Swanston Street to the station site.
The roadheaders – named Lily, Sharon and Clara – have been operating around 25 metres below one of Melbourne’s busiest streets. The machines weigh up to 118 tonnes and are equipped with cutterheads that can smash through rock three times harder than concrete.
The state-of-the-art Town Hall Station will give commuters access to Melbourne landmarks such as Federation Square, Southbank, the Arts Centre, St Paul’s Cathedral and other popular tourist locations, and allow passengers to switch easily from Metro Tunnel services to City Loop services at Flinders Street Station.
The Metro Tunnel Project has been making significant progress across all sites during the coronavirus pandemic, with four tunnel boring machines (TBMs) now hard at work underground. More than 3.3 kilometres of tunnel have been completed since September.
Next year, following roadheader excavation of the tunnels through the CBD stations, TBMs will carve out the twin tunnels between Town Hall Station and State Library Station, 30-40 metres below Swanston Street.
The Metro Tunnel is on track to be completed by 2025. When finished, it will create capacity for more than a half a million extra passengers a week during peak times across Melbourne’s train network.