By Megan Gorrey
They are the twin transport mega-projects reshaping the way commuters move around the city – and they have passed within tens of metres of each other, deep beneath the ground in North Sydney.
Giant road-headers digging the second stage of the NSW government’s $7.4 billion Western Harbour Tunnel between Cammeray and Birchgrove via Waverton have slowly broken their way through the rocky ground above the $21.6 billion metro line underneath Sydney Harbour and the city centre.
Road-headers have carved a tunnel overlapping the metro rail line near Victoria Cross station. Credit: NSW government
Since they launched from the Warringah Freeway one year ago, six tunnelling machines have worked around the clock to dig a 2.9-kilometre stretch of the underground three-lane road tunnel.
The tunnel, which passes 42 to 53 metres under North Sydney, now overlaps the massive caverns for the metro rail line, which are between 25 and 40 metres further below the surface.
Roads Minister John Graham said more than 60 per cent of tunnelling was complete, and the project was on schedule to provide the first new road crossing of Sydney Harbour in more than 30 years.
“Anyone who has crossed the harbour by road knows the system is constrained and the Western Harbour Tunnel will provide much-needed relief, slashing travel times by 20 minutes on a journey from North Sydney to Leichhardt or Sydney Olympic Park,” Graham said.
The 6.5-kilometre tunnel, which will be tolled, is due to open to motorists in 2028, later than its original completion date of 2025-26.
Once finished, the tunnel will connect motorists between the Warringah Freeway and Rozelle Interchange, allowing those travelling between the city’s north and west to bypass traffic in the CBD.
The government hopes the route will ease congestion on the Harbour Bridge, Harbour Tunnel, Anzac Bridge and Western Distributor.
Late next year, massive tunnel boring machines will be assembled at Birchgrove before they start to dig their way north under the harbour to Waverton.
Tunnelling for the Western Harbour Tunnel is now more than 60 per cent complete, with the second stage of work having passed above the Sydney Metro tunnel at North Sydney on its way towards Waverton.
The road-headers recently passed under North Sydney Council chambers on Miller Street, near Victoria Cross station, and are churning through 25 metres of rock per week en route to Waverton.
Each machine can excavate 1000 tonnes – equivalent to the weight of three Boeing 747-200 planes – of rock per day. Transport for NSW and stage two contractor Acciona are trialling a remote control road-header, which can be operated by workers 200 metres from the rock face, to carve the tunnels.
Construction of the first stage of the twin 1.7-kilometre tunnels from the WestConnex interchange at Rozelle to Birchgrove began in July 2022 and work is nearly complete.
The former Coalition government had decided to dig deeper tunnels for the main section of the motorway between Birchgrove and Waverton, ditching earlier plans to lay large tubes in a trench on the harbour floor.
NSW Labor has vowed to keep the Western Harbour Tunnel in public hands as part of a long-term strategy to increase the number of state-owned toll roads and reduce Transurban’s stranglehold on Sydney’s motorway network.
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