Australia’s longest railway tunnels are a step closer to being completed with work now finished at the massive factory building the internal concrete lining of Sydney Metro Northwest’s twin tunnels. The 15 kilometre twin tunnels from Bella Vista to Epping need 16,000 concrete rings to line them, which are put in place by the four tunnel boring machines as they dig forward. The factory at Bella Vista made almost 100,000 concrete segments which form these rings. The last segment has come off the production line, with workers celebrating its completion. It joins those still drying in a massive outdoor storage area beside Old Windsor Road. The segments were all made over the past 18 months. Key production facts include:
- The equivalent of 60 Olympic swimming pools of concrete was used to make the segments, or 3,600 tonnes.
- The segments would reach 26 kilometres into the sky, or nearly three times the height of Mt Everest if stacked on top of each other.
- Each segment weighs about 4 tonnes.
- Each segment’s specific location in the tunnels is recorded and they are all individually barcoded.
- The most segments produced in one day was 437 (May 27 this year).
Tunnelling on the $8.3 billion Sydney Metro Northwest is now more than 90 per cent complete, with two of the four tunnel boring machines finished work and dismantled – more than 28 of the 30 kilometre tunnelling task is finished.