en.Wedoany.com Reported - The River Torrens to Darlington (T2D) tunnel project, the largest infrastructure project in the history of South Australia, officially commenced tunneling in early July 2026. The project's first Tunnel Boring Machine (TBM), named "Mary," has been launched at the southern work site in Clovelly Park, beginning excavation of the first 4.5-kilometer southbound tunnel. The second TBM, "Catherine," will soon be launched at the same site to excavate a parallel southbound tunnel; the third TBM, "Elizabeth," will be launched at the northern work site in Hilton to construct a 2.2-kilometer northbound tunnel.
The T2D project represents the final 10.5-kilometer section of Adelaide's North-South Corridor, with a total investment of AUD 15.4 billion (approximately EUR 9.35 billion), funded equally by the Australian Federal Government and the South Australian Government at AUD 7.7 billion each. Upon completion, the project will create a continuous 78-kilometer non-stop highway from Gawler to Old Noarlunga, allowing drivers to bypass 21 sets of traffic lights and save up to 40 minutes of travel time during peak hours.
All three TBMs are supplied by Herrenknecht, a world-leading manufacturer of tunnel boring equipment. Each machine measures approximately 100 meters in length, 15 meters in diameter, and weighs about 3,500 tons. The TBMs are named after three pioneers who advanced the women's suffrage movement in South Australia—Mary Lee, Catherine Helen Spence, and Elizabeth Webb Nicholls. Each TBM will operate continuously 24 hours a day, advancing approximately 8 to 10 meters daily, with up to 20 professionals working inside each machine during peak periods.
To meet the power demands of three TBMs operating simultaneously, the project has constructed two substations—the Tonsley East substation powers Mary and Catherine, while the Richmond East substation powers Elizabeth. The Richmond East substation can meet the electricity needs of 5,000 households, providing a dedicated 22,000-volt power supply line. The project also built a TBM launch shaft measuring 120 meters by 50 meters by 20 meters, with approximately 120,000 cubic meters of earth and rock, weighing over 343,000 tons, previously excavated.
The simultaneous operation of three TBMs enables synchronized excavation of the northbound and southbound tunnels, with the project expected to be completed by 2031. Once finished, the T2D project will divert approximately 130,000 vehicles of daily traffic into the underground tunnels, significantly alleviating surface traffic congestion in Adelaide.
