Two of Sydney Metro Northwest's four mega tunnel boring machines (TBMs) have now finished their job building Australia's longest ever railway tunnels – with TBM4 Maria becoming the second when she reached the end of the line at Epping on Thursday 29 October 2015.
Maria completed her journey from Cherrybrook in just over 9 months and dug almost 6 kilometres of Australia's longest railway tunnels. The TBM was one of four mega tunnelling machines delivering the 15 kilometre twin tunnels from Bella Vista to Epping.
Her achievement coincided with the project completing more than 90 per cent of tunnelling. 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:
- 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 135 metres.
TBM4 Maria will now be dismantled and brought to the surface in pieces in a series of precision operations over coming weeks.