Tunnelling complete


Tunnelling has finished on Australia’s longest railway tunnels, with the last of four giant tunnelling machines completing work on Sydney Metro Northwest.

Tunnelling has finished on Australia’s longest railway tunnels, with the last of four giant tunnelling machines completing work on Sydney Metro Northwest. NSW Premier Mike Baird, Minister for Transport and Infrastructure Andrew Constance and local MPs witnessed the historic breakthrough as Tunnel Boring Machine (TBM) 2 ‘Florence’ arrived at what will become Cherrybrook Station. “Today everyone can be proud at what’s been achieved, with this long-promised critical public transport project taking shape before our eyes,” Mr Baird said. “This rail line will  transform the lives of people in Sydney’s north-west, enabling commuters to catch a train every four minutes in the peak.” Mr Constance says workers have collectively spent more than 360,000 hours underground building the tunnels. “I pay tribute to all the men and women who have worked on this massive project and ensured tunnelling has finished about two months ahead of schedule,” Mr Constance said. “About 2.7 million tonnes of Sydney Sandstone and shale has been excavated to complete the job. “It’s taken just 16 months for our four giant tunneling machines to deliver today’s result, and we’re only just getting started, as we prepare for construction of the next stage of the Metro project.” More than 4,600 people worked on the Sydney Metro Northwest tunnelling contract, most of them from the Western Sydney region. The facts on the $1.15 billion tunnelling contract:

  • Sydney Metro Northwest includes Australia’s longest railway tunnels – twin 15 kilometre tunnels from Bella Vista to Epping – and a 4 kilometre elevated skytrain viaduct from Bella Vista to Rouse Hill.
  • Sydney Metro Northwest is the first transport infrastructure project in Australian history to use four TBMs at once.
  • Tunnelling started in September 2014. It took 16 months to build 30 kilometres of tunnels.
  • Each TBM weighed more than 900 tonnes, or 560 Holden Commodores, and was almost 120 metres long.
  • Each TBM operated underground 24-7 and built an average of 173 metres of tunnel a week.
  • More than 1.7 million tonnes of crushed rock was excavated by the TBMs, mostly Sydney Sandstone and shale – the equivalent of 423 Olympic swimming pools.
  • 100 per cent of crushed rock from tunnelling was recycled and used on commercial, industrial and housing developments across Greater Western Sydney, including at Bunnings at Blacktown and an environmental re-use project at Prospect Dam.
  • Another 1 million tonnes of rock was excavated from the new metro railway station sites at Bella Vista, Norwest, Castle Hill, Showground and Cherrybrook.
  • The four TBMs had 2,006 cutter teeth replaced due to the forces of tunnelling, each weighing 230 kilograms.
  • On major tunnelling projects around the world, underground workers look to Saint Barbara for protection. Because of this, machines that work underground are traditionally given female names. Three of the four TBMs were named in community competitions under the theme: ‘Women who have made a positive contribution to life in Sydney’.
  • TBM1 Elizabeth was named after local pioneer Elizabeth Rouse; TBM2 after Australia’s first female architect and civil engineer Florence Taylor; TBM3 Isabelle was named on behalf of the workers by the tunnel builders after Isabelle Andersen, aged 4, the daughter of a worker, and TBM4 Maria was named after Aboriginal rights advocate Maria Lock.
  • A purpose built factory at Bella Vista made 98,184 concrete segments, which were turned into 16,290 concrete rings to line the inside of the twin tunnels and keep them waterproof.
  • TBM3 Isabelle reached the deepest point of the project in March 2015 – 58 metres beneath Thompson’s Corner at West Pennant Hills.

Elizabeth resurfaces

TBM1 sees light at the end of the tunnel

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