Major tunnelling is now complete at the Sydney Metro – Western Sydney Airport project in New South Wales.
The milestone was achieved after tunnel boring machine (TBM) Marlene arrived at the St Marys Metro Station site and achieved the final tunnel breakthrough for the project.
The machines spent 14 months building two separate sets of tunnels at either end of the alignment. The job required the excavation of 1,863,460 tonnes of material, enough and the installation of 69,966 concrete segments to line the new tunnel walls.
TBMs Marlene and Catherine carved out the 4.3km tunnels from Orchard Hills, under the M4 Motorway and the Great Western Highway to reach St Marys.
TBMs Eileen and Peggy constructed the 5.5km tunnels from Airport Business Park, underneath the new Western Sydney International Airport, to Aerotropolis.
The final TBM breakthroughs occurred in the following succession; Catherine completed the first tunnel at the St Marys site in May 2024, Elieen broke through at the Aerotropolis site, Peggy made the penultimate breakthrough in June before Marlene made the final breakthrough on 20 June 2024.
Now that tunnelling has finished, the TBMs will be dismantled, washed and lifted by tower cranes onto trucks before they are shipped back to the TBM manufacturer.
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