Sydney Harbour tunnel construction progresses with massive boring machines

Construction is underway on the $7.4 billion Western Harbour Tunnel motorway in Sydney, involving massive tunnel boring machines (TBMs) working beneath Sydney Harbour. One 4,400-tonne machine, named Barangaroo, has begun a 1.5-kilometre drive northwards beneath Birchgrove. A second machine, Patyegarang, has already progressed over 110 metres from its launch chamber.

The project, managed by Spanish contractor Acciona, faces technical challenges as the machines navigate a 200-metre section of clay, silt, and sand known as a paleo channel. To mitigate risks, the machines will pass through this hazardous ancient riverbed one at a time. Once completed, the three-lane tunnels will connect the Warringah Freeway on the north shore to the WestConnex toll road at Rozelle.