Together these 15.7m diameter CREG TBMs will bore the 1.5km underwater section of the tunnel under Sydney Harbour to the Warringah Freeway at North Sydney.
The two 28m high caverns are among the largest ever excavated in Australia. They are located just 230m from the edge of Sydney Harbour ready for the TBMs’ dive.
The milestone comes as the second TBM arrived in Sydney on 21st October, joining its twin, which landed in August.
Over the coming months, workers from project contractor Acciona, will assemble the TBMs piece by piece inside the Birchgrove caverns using a 500-tonne gantry crane. Once launched, they’ll tunnel around the clock, supported by 40 skilled workers per shift, as they begin their epic journey beneath the harbour.
The TBMs will begin excavating under the harbour in the first half of 2026 once the TBMs, comprising 263 major parts each, have been assembled in painstaking correct order. TBM assembly will take several months. They are expected to take around a year to complete their work.
When complete, the Western Harbour Tunnel will provide a seamless 6.5km connection between the Warringah Freeway and the Rozelle Interchange, reducing congestion, improving travel times, and strengthening connections across the city’s north, west and south.
The Western Harbour Tunnel is on track to open to traffic in 2028 and will remain in public ownership, ensuring the long-term benefits of this investment stay with the people of NSW. The project is supporting 7,000 jobs over the course of construction.
Minister for Roads Jenny Aitchison said: “Today, the Minns Labor Government is one step closer to delivering the Western Harbour Tunnel.
“This is a once-in-a-generation project, with the Minns Government on track to deliver Sydney’s third road harbour crossing.
“After 12 years of Liberal-National privatisation, we are building this project as a public asset for the people of NSW.
“These giant caverns are vast enough to fit six Emerald class Sydney ferries each, but once the TBMs are assembled inside them, there will only be around 1-2m between each TBM and the launch chamber walls.
“The scale of this project is absolutely breathtaking. More than 4,800,000 tonnes of material already have been excavated across the Western Harbour Tunnel project to date.
“The Western Harbour Tunnel TBMs are the largest in the Southern Hemisphere and the largest in the world to be assembled underground. The mega-machines were shipped to Australia in 263 pieces, with 125 shipping containers of other components, and our team is now preparing them for launch.
“In a few days, the TBM parts will be loaded onto specialised heavy vehicles and transported into the launch chambers via the City West Link portal.
“The Western Harbour Tunnel is on track to open in 2028 and importantly, will remain in public ownership.”
