The third Sydney Metro Northwest tunnel boring machine (TBM) to finish tunnelling has been pulled out of the ground in a precision operation. TBM1 Elizabeth recently finished her journey at Cherrybrook after digging 9 kilometres of Australia’s longest railway tunnels. Its massive 105-tonne cutter-head has been lifted 10 metres to the surface using a 600 tonne crane. Tunnelling is now 99 per cent complete with only one mega tunnelling machine, TBM2 Florence, remaining underground and less than 500 metres of tunnelling to go.
TBM1 Elizabeth was one of the four mega machines delivering the twin 15 kilometre tunnels between Bella Vista and Epping and the first to start tunnelling in September 2014. Named after local colonial pioneer Elizabeth Rouse, TBM1 chewed through more than 700,000 tonnes of Sydney Sandstone and shale and went through 735 hardened steel teeth due to the forces of tunnelling on her 15-month journey from Bella Vista to Cherrybrook.
Specialist crews have been dismantling TBM1 since early December with a carefully choreographed operation required to retrieve her 105-tonne cutter-head and bring it to the surface at Cherrybrook. Cherrybrook is one of eight new metro stations on Sydney Metro Northwest, the first stage of Sydney Metro – Australia’s biggest public transport project. New metro services start in the first half of 2019 with a train every four minutes in the peak.