The second Sydney Metro Northwest tunnel boring machine (TBM) to complete its journey has resurfaced, with 28km of the 30km tunnelling scheme now complete.
TBM Maria’s 105t cutterhead was lifted 25m to the surface after excavating almost 6km of Australia’s longest railway tunnels.
Maria tunnelled through more than 550,000t of Sydney sandstone and shale, and used more than 450 hardened steel teeth due to the forces of tunnelling.
The TBM was one of four machines delivering the twin 15km tunnels between Bella Vista and Epping.
Only two TBMs remain on the project and are currently tunnelling between Castle Hill and Cherrybrook.
The Epping site will be used for fresh air tunnel ventilation and as an emergency access point to the tunnels when Sydney’s new trains start running in the first half of 2019.