Image courtesy of Rail Projects Victoria
Transforming the Way People Move Around Melbourne
The Metro Tunnel will create a new end-to-end train line from Sunbury to Cranbourne/Pakenham, with high capacity trains, twin nine km rail tunnels and five new underground stations at Arden, Parkville, Anzac. They will connect directly to the City Loop through two new CBD stations at the State Library and Town Hall.
The Metro Tunnel will create capacity on Melbourne’s train network to enable more than a half a million additional passengers per week to use the rail system during the peak periods.
WSP, in a design joint venture with Arcadis and Arup (AAW), is working as part of the CYP D&C – led by Lendlease, John Holland and Bouygues Construction to deliver the tunnel, civil, structure, surface transport, and rail infrastructure, together with the mechanical, electrical and hydraulic design. We are also delivering the specialist services including tunnel ventilation, fire and life safety, security and blast assessment, pedestrian modelling, noise and vibration, environmental and sustainability services including contaminated land management.
Meeting the Challenge of Tunnelling Under a Thriving CBD
Building the Metro Tunnel presents many challenges, including:
- Managing disruption to residents, businesses and public events
- Minimising potential impacts on road traffic, pedestrians, cyclists and existing public transport
- Navigating existing underground infrastructure
- Excavating through a range of varied geological conditions
- Tunnelling under two significant waterways, the Yarra River and Moonee Ponds Creek
- Managing the removal and disposal of large amounts of excavated material and soil.
Along its route, the depth of the Metro Tunnel will be up to 40 metres under Swanston Street, at the northern edge of the CBD, where the new tunnels pass under the existing City Loop tunnels. From the Town Hall Station under Swanston Street at Flinders Street, the tunnels will travel below the Yarra River before passing under CityLink on their way to the new Anzac Station under St Kilda Road.
Creating Space with CBD Excavation
To keep Swanston Street open while the Metro Tunnel is built, access shafts up to 11 storeys deep are being dug next to the new station entrances. These shafts are being used to transport machinery, equipment and workers underground, so they can excavate and line the station caverns below Swanston Street.
The Metro Tunnel's two new CBD stations (State Library and Town Hall) will be built as 'trinocular' caverns whereby three overlapping tunnels are mined by road headers, creating a wide-open space that allows the concourse and platforms to be integrated on a single level.
The result will be a spacious station with vaulted ceilings, rather than two separate tunnels separated by a cross-passage. The total platform width at the CBD stations will be around 19 metres – some of the widest underground metro platforms in the world.