Two of Sydney Metro Northwest’s four mega tunnel boring machines have now finished their job building Australia’s longest ever railway tunnels – with TBM4 Maria reaching the end of the line at Epping.
“Just over 26km of the 30km tunnelling work is now complete,” Mr Constance said.
“Maria has set a cracking pace, digging almost 6km in just over nine months after starting her big dig in Cherrybrook early this year.
“Tunnelling is now almost 90 per cent complete as we count down to finishing the twin 15km railway tunnels from Bella Vista to Epping.”
The 900-tonne TBM was delivered to the Cherrybrook tunnelling site in 18 shipping containers and 27 large pieces and was assembled by a crew of more than 70 workers. Since launching from Cherrybrook on 13 January 2015, TBM4 Maria has:
- Excavated more than 550,000 tonnes of crushed rock, both sandstone and shale;
- Had 452 hardened steel cutters on her cutter head replaced;
- Installed just over 20,000 concrete segments to line the new rail tunnel;
- Was home to tunnelling crews of 15 workers who have spent more than 75,000 hours underground;
- Achieved an average weekly tunnelling distance of 135m.
TBM4 Maria will now be dismantled and brought to the surface in pieces in a series of precision operations over coming weeks.
TBM3 Isabelle, which finished work at Epping just last month, has already been removed from the site.
When Sydney’s new metro trains start running in the first half of 2019, the Epping Services Facility will be used for fresh air tunnel ventilation and as an emergency access point to the tunnels below.