01/07/2026
Torrens to Darlington (T2D) Project - South Tunnel Precinct I July 2026 Update🏗️
South Australia has reached a major milestone on its largest infrastructure project, with tunnelling now underway on the $15.4 billion River Torrens to Darlington (T2D) Project.
Tunnel Boring Machine Mary has begun excavating the first 4.5‑kilometre Southern Tunnel, advancing 8–10 metres per day with a 24/7 workforce of up to 20 specialists. Her assembly began after components arrived in October 2025, lifted piece‑by‑piece into the launch box using a 500‑tonne gantry crane.
Mary is one of three TBMs—each around 100 m long, 15 m in diameter and weighing 3,500 tonnes—named after South Australian suffragists Mary Lee, Catherine Helen Spence and Elizabeth Webb Nicholls. TBM Catherine will soon begin the parallel Southern Tunnel, while TBM Elizabeth will launch from Hilton to build the 2.2‑kilometre Northern Tunnels.
Using three TBMs enables simultaneous construction of the Northern and Southern tunnels, supporting delivery of a non‑stop South Road by 2031. T2D completes the final 10.5 kilometres of the North–South Corridor, creating 78 kilometres of uninterrupted motorway between Gawler and Old Noarlunga.
The Australian and South Australian Governments have each invested $7.7 billion in the project.
With tunnelling underway, the public can track Mary’s progress via the new online TBM Tracker, with updates for Catherine and Elizabeth to follow once they commence tunnelling.
https://www.t2d.sa.gov.au/tbm-tracker