TBM 4 Maria resurfaces after a job well done


The second Sydney Metro Northwest tunnel boring machine to finish tunnelling

The second Sydney Metro Northwest tunnel boring machine (TBM) to finish tunnelling has been pulled out of the ground in a precision operation, with its massive 105-tonne cutter-head lifted 25 metres to the surface.   TBM4 Maria recently finished her journey at Epping after digging almost 6km of Australia’s longest railway tunnels. She was one of the four mega machines delivering the twin 15km tunnels between Bella Vista and Epping. Only two TBMs remain, and are currently digging between Castle Hill and Cherrybrook.   Tunnelling has now passed the 92 per cent mark on Sydney Metro Northwest, with 28 of the 30 kilometre tunnelling work complete. TBM4 Maria chewed through more than 550,000 tonnes of Sydney sandstone and shale and went through more than 450 hardened steel teeth due to the forces of tunnelling.   Specialist crews have been dismantling TBM4 since she ended her nine-month journey in late October with a carefully choreographed operation required to retrieve her 105-tonne cutter-head and bring it to the surface.   TBM4 Maria was named after 19th century North West Sydney Aboriginal rights advocate Maria Lock (c.1805 -1878).   The Epping site will be used for fresh air tunnel ventilation and as an emergency access point to the tunnels below once Sydney’s new trains start running in the first half of 2019.

TBM3 Isabelle has been dismantled

Tunnelling a step closer to completion

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