ACCIONA has recently completed factory acceptance testing for its second tunnel boring machine (TBM), Barangaroo, in China, marking a major milestone in the delivery of the NSW Government’s Western Harbour Tunnel project in Sydney.
Named in honour of the Cammeraygal fisherwoman from the Sydney Harbour region, Barangaroo will join sister TBM Patyegarang as the largest TBMs ever used in the southern hemisphere, each with a cutterhead diameter of 15.71 metres.
The machines are central to ACCIONA’s innovative tunnelling approach, which avoids dredging the harbour and significantly reduces environmental and community impacts.
Andrew Marsonet, Project Director, said the team’s approach from the outset has been to challenge conventional methods.
“The original plan involved an immersed tube tunnel, which would have disturbed marine ecosystems and heritage areas,” Mr Marsonet said. “We proposed a deeper tunnel alignment that avoids these impacts and delivers a more sustainable solution.”
Western Harbour Tunnel will connect North Sydney to Rozelle via a new motorway beneath Sydney Harbour. Stage 2 of the project includes tunnelling from Cove Street, Birchgrove, to the Warringah Freeway, near North Sydney, as well as full tunnel fit out works.
ACCIONA partnered with Chinese manufacturer CREG to design and build the two purpose-built TBMs.
CREG designers were embedded on site in Australia during the design phase and ACCIONA personnel embedded in China during fabrication, to co-develop innovative features, collaborate on the machines’ design, and ensure they met the project’s unique requirements.
Christian D’Hondt, Construction Manager for the WHT project, highlighted the project’s pioneering construction methods.
“Both TBMs will be assembled and launched from underground chambers, a first for Australia,” Mr D’Hondt said. “This method reduces surface disruption and improves safety and efficiency.”
The TBMs are also equipped with robotic systems to automate the replacement of cutter discs, eliminating the need for personnel to work in hyperbaric conditions. Additional robots will assist in preparing tunnel segments for installation, further enhancing safety and productivity.
The first TBM, Patyegarang, completed its journey from China to Sydney in August 2025, with Barangaroo, following shortly after in October.
Western Harbour Tunnel represents a significant advancement in urban tunnelling, combining engineering innovation with environmental stewardship.
As construction progresses, the project is set to redefine how major infrastructure is delivered in complex urban environments.