Last Sydney TBM now out of the ground

The last Sydney Metro Northwest tunnel boring machine has been pulled out of the ground in a precision operation. Tunnel Boring Machine 2 Florence finished her journey at Cherrybrook on January 14 after digging 9km from Bella Vista, marking the end of tunnelling for Australia’s longest railway tunnels.

Florence has been progressively dismantled and her massive 105-tonne cutter head has now been lifted 10m to the surface. Florence was one of four mega borers building the twin 15km tunnels from Bella Vista to Epping, which were completed in 16 months.

Named after Florence Taylor – Australia’s first female architect, structural engineer and civil engineer – TBM2 chewed through more than 768,000 tonnes of Sydney Sandstone and shale and went through 616 hardened steel teeth due to the forces of tunnelling.

Cherrybrook is one of eight new metro stations on Sydney Metro Northwest, the first stage of Sydney Metro – Australia’s biggest public transport project.

Sydney’s new metro trains start in the first half of 2019 with a service every four minutes in the peak.

The facts on the $1.15bn tunnelling contract:

1. Sydney Metro Northwest includes Australia’s longest railway tunnels – twin 15km tunnels from Bella Vista to Epping – and a 4km elevated skytrain viaduct from Bella Vista to Rouse Hill.
2. Sydney Metro Northwest is the first transport infrastructure project in Australian history to use four TBMs at once.
3. Tunnelling started in September 2014. It took 16 months to build 30km of tunnels.
4. Each TBM weighed more than 900 tonnes, or 560 Holden Commodores, and was almost 120m long.
5. Each TBM operated underground 24-7 and built an average of 173m of tunnel a week.
6. 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.
7. 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.
8. Another 1 million tonnes of rock was excavated from the new metro railway station sites at Bella Vista, Norwest, Castle Hill, Showground and Cherrybrook.
9. The four TBMs had 2,006 cutter teeth replaced due to the forces of tunnelling, each weighing 230 kg.

1. 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.