The Victorian Government will immediately commence works on the Metro Tunnel Project, having launched a road header machine to dig the underground cavern needed for the new State Library Station.
The 118t, 15m-long machine has been lowered almost 30m underground in pieces before being reassembled ahead of digging.
Road headers are massive excavating machines fitted with a mounted cutter head that will mine out the caverns for both Metro Tunnel CBD stations — State Library and Town Hall.
A total of six road headers will be used in the CBD as part of the project, with the first State Library road header starting work on mining out of the A’Beckett Street shaft towards Swanston Street.
To minimise disruption during the construction of the new State Library Station, access shafts are being built at A’Beckett Street, Franklin Street east and west, and La Trobe Street. These shafts allow machinery, equipment and workers to be transported underground to build the new station in heavily built-up areas.
In 2019, a second road header will start its journey from the A’Beckett Street shaft towards La Trobe Street, and a third from Franklin Street east towards A’Beckett Street, as the three machines work together to form State Library Station.
The equivalent of almost 70 Olympic swimming pools of rock and soil will be excavated by the road headers during the construction of State Library Station, which will be located directly beneath Swanston Street, between La Trobe Street and Franklin Street.
The machines will excavate around 1500t of rock each day, with the cutter head able to smash through rock three times harder than concrete. Each road header includes a highly advanced computer used to accurately excavate the cavern.
Round-the-clock excavation continues within the Franklin St East acoustic shed, with the access shaft currently at a depth of around 30m. Piling is currently underway to support the excavation of access shafts at Franklin Street West, and on the corner of La Trobe and Swanston streets.
The government’s Metro Tunnel is one year ahead of schedule, with the first train due to run through the Metro Tunnel in 2025.
Victorian Premier, Daniel Andrews, said, “We’re not wasting a minute, with major construction ramping up on the Metro Tunnel, so we can run more trains more often.”