The assembly of the River Torrens to Darlington (T2D) Project’s first tunnel boring machine (TBM) has commenced.
The machines, crucial to the completion of the $15.4 billion non-stop South Rd plan, will be approximately 100m in length and 15m in diameter – roughly the height of the goalposts at Adelaide Oval.
Two TBMs will launch from the Southern Precinct at Clovelly Park and be used to construct the twin 4.5km 
Southern Tunnels.
A third machine will launch from the Central North Precinct at Richmond to construct the twin 2.2km Northern Tunnels.
When fully assembled each TBM will weigh approximately 3500 tonnes – but first they must be put together.
The 15m-wide cutterhead of the first TBM has already been pieced together, and welding is now underway, a process expected to take up to eight weeks.
All remaining components for the first TBM have now arrived onboard the second equipment shipment, including the main drive which weighs approximately 370 tonnes.
This shipme
nt, which included the cutterhead and tailskin for TBM 2, will be gradually transported to the Project’s Southern Precinct site in Clovelly Park.
Over the weekend the centrepiece of the cutterhead for the second TBM travelled the 25km journey from Port Adelaide to the Southern Precinct site.
The TBMs will each undergo a six-month assembly and commissioning process on site, before tunnelling is expected to begin in the second half of 2026.
The T2D Project will be the only major road tunnel project in Australia to utilise three large diameter TBMs, which have been purchased from world-leading tunnelling manufacturer Herrenknecht.
The procurement of three TBMs means both the Northern and Southern tunnels can be constructed concurrently.
You can learn more about the T2D project here.
