Western Harbour Tunnel project reaches major milestones in Sydney

The A$4.24 billion Western Harbour Tunnel project in Sydney has reached significant construction milestones. Engineers have completed the excavation of two massive underground reception chambers beneath Waverton. These chambers, measuring up to 23 metres high, are designed to accommodate the dismantling of the Patyegarang and Barangaroo tunnel boring machines (TBMs), which are the largest ever used in the Southern Hemisphere.

The Patyegarang TBM is currently approaching the halfway point of its 1.5km drive from Birchgrove. Engineers have noted that the upcoming section involves navigating a 200-metre stretch of clay, silt, and sand under the harbour, which is considered the riskiest stage of the operation. The second machine, Barangaroo, is expected to pass through a paleo channel by March.

In conjunction with the tunnel works, the Warringah Freeway upgrade is nearing completion after five years of construction. Final traffic changes are expected within weeks, including the conversion of a reversible lane into a permanent northbound lane and the opening of a new northbound on-ramp from High Street. These upgrades are intended to support the tunnel, which is scheduled to open in late 2028 to allow motorists to bypass the Sydney CBD.