Breakthrough! Sydney Metro tunnels reach major milestone

TBM 'Marlene' breaks through.
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Two tunnel boring machines (TBMs) are halfway to St Marys after each building 2.4 kilometres of tunnel for the Sydney Metro – Western Sydney Airport project.

TBMs Catherine and Marlene reached the milestone when they broke through at the Claremont Meadows services facility shaft, after launching at the Orchard Hills Station site in July and August 2023 respectively.

Tunnelling at an average speed of 120 metres a week, the TBMs are carving out the twin 4.3-kilometre tunnels to the new St Marys Metro Station site.

They have removed 600,000 tonnes of spoil so far, enough to fill about 95 Olympic swimming pools, and installed 17,820 precast concrete segments as they tunnelled under the M4 Motorway to the 21-metre-deep services shaft.

The TBMs will now traverse the 16-metre-diameter services shaft, which is used to supply materials like concrete and steel, before being relaunched to complete their journey. They are expected to reach St Marys in mid-2024.

TBM ‘Catherine’ breaks through.

A further two TBMs, Eileen and Peggy, are building the two 5.5-kilometre southern tunnels from Airport Business Park to the Aerotropolis. Both are respectively about 3 kilometres into their journeys and are due to arrive at the Aerotropolis in late 2024.

The Sydney Metro – Western Sydney Airport line will be operational when the new international airport opens for passenger services, with the end-to-end journey time between the St Marys Metro Station and Aerotropolis Station to take around 20 minutes.

“We are one step closer to seeing transformative public transport delivered for Greater Western Sydney,” said Federal Infrastructure and Transport Minister, Catherine King.

“When the new metro line opens, passengers will have a world-class transport option directly to the new Western Sydney International (Nancy-Bird Walton) Airport and major job hubs, including the new Aerotropolis.”

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