South Australia selects five-firm consortium to finish ‘largest infrastructure project’

Render of the River Torrens to Darlington twin-tunnel access and exit. (Image courtesy T2D project website)

Peter Malinauskas, Premier of South Australia, noted the expansive programme has been years in the making.

“For decades, South Australians have waited for a non-stop trip from north to south through Adelaide [and], finally, we are getting it done,” he said, adding the project will “see thousands of South Australians employed building the biggest infrastructure project in the state’s history.”

The project is a nine-part build seeking to expand and improve 78km of motorway across the City of Adeliade from Gawler to Old Noarlunga townships.

Eight parts have already been completed (one section as early as 2009) with only the River Torrens to Darlington tunnel boring machine (TBM) project remaining. At a cost of AU$15.4 billion (US$10.1 billion), it’s the priciest segment of the more than $13billion project.

“The current roadway is not working effectively and will not be able to handle the projected number of vehicles that will need to use the road or cater for the size of freight carriers wanting to travel along it,” explained the South Australian government. “In response, the Australian and South Australian Governments are working collaboratively to expand the route by creating a dedicated non-stop North-South Corridor.”

About the River Torrens to Darlington TBM scheme

Map of the scope of the River Torrens to Darlington TBM project in Adelaide, South Australia, Australia. (Image courtesy T2D project website)

Abbreviated ‘T2D’, the River Torrens to Darlington section will add the final 10.5km stretch of the massive infrastructure build.

Consisting of underground twin tunnels, the stretch of road will serve as a bypass of 21 sets of traffic lights in and around Adelaide.

“The project will not only revolutionise the way locals move around their region, but unlock new transport opportunities for tourists to visit the area as well,” said Australia Minister for Infrastructure, Transport, Regional Development and Local Government Catherine King.

Three TBMs will be used, which is one more than originally planned. The introduction of a third TBM means the tunnels can be constructed simultaneously, which project managers believe will help finish the build prior to the planned 2031 deadline.

“We’ll have three TBMs operating instead of two – guaranteeing this project will be delivered on time,” added Premier Malinauskas. “In fact, once the TBMs arrive next summer, we’re hopeful the delivery deadline can be brought forward.

“Once complete, this project will see traffic move between West Hindmarsh and Darlington in just nine minutes, saving 30 to 40 minutes of travel time during peak hour,” he concluded.

South Australian officials expected the scheme to create about 5,500 construction jobs annually until completion.

Staging work is expected in the coming weeks with principal construction anticipated for 2025. The TBMs will be employed in the latter half of 2026.