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Sydney’s new metro railway will run through purpose designed and built tunnels.
A number of factors determine the tunnel route and alignment. These include:
- the location, depth and structure of the stations
- vertical track grade
- rock conditions
- track curvature, to allow train speeds of up to 100 kilometres an hour
- the physical constraints of the route, including crossing under Sydney Harbour.
Stage 1: Sydney Metro Northwest
Tunnelling finished in January 2016 on Australia’s longest railway tunnels – twin 15 kilometre tunnels from Bella Vista to Epping as part of Stage 1 of Sydney Metro.
Stage 2: Sydney Metro City & Southwest
Tunnelling started in October, 2018 on the twin tunnels from Chatswood to Sydenham, including under Sydney Harbour and through the Sydney CBD.
Tunnel boring machine progress
- TBM Mum Shirl = 4.3 Km
- TBM Nancy = 4.93 Km
- TBM Wendy = 3.22 Km
- TBM Mabel = 2.77 Km
About our tunnels
The end of tunnelling Cherrybrook
Sydney tunnel depths
Inside the tunnels
30 km of tunnels in 3 minutes: Delivering Australia's longest railway tunnels
How a typical TBM works
Completed Castle Hill cavern
A specialised TBM will be used to cross Sydney Harbour
Dismantling TBM1 Elizabeth
Sydney Metro tunnel cross section
Our tunnel boring machines
Five tunnel boring machines (TBMs) are being used to deliver the tunnels between Chatswood and Sydenham for Sydney Metro City & Southwest. This includes a specialised TBM for the section under Sydney Harbour because of the ground and rock conditions found at the bottom of the harbour.
Four mega tunnel boring machines built the twin tunnels on Sydney Metro Northwest. This was the first time in Australian history four TBMs were used on the one transport infrastructure project.
Naming the TBMs
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.
Sydney Metro City & Southwest TBMs
TBM1 Nancy was named in honour of Australian aviation pioneer Nancy Bird Walton OBE, the first female pilot in the Commonwealth to carry passengers and the founder of the Australian Women Pilots’ Association.
TBM1 Nancy cutterhead
TBM2 Mum Shirl was named in honour of Colleen Shirley Perry, a Wiradjuri woman who dedicated her life to her community, raising 60 foster children and was involved in establishing legal, medical, housing and cultural services for the Aboriginal community.
TBM3 Wendy was named after Wendy Schreiber, a volunteer at Bear Cottage – the only children’s hospice in NSW and long standing charity partner for the Sydney Metro tunnelling contractor John Holland CPB Ghella.
Sydney Metro Northwest TBMs
TBM1 Elizabeth was named after colonial pioneer Elizabeth Rouse, by Alexandra Marshall from Rouse Hill Anglican College after winning a school competition.
TBM2 Florence was named after Australia’s first female engineer and architect, Florence Mary Taylor.
TBM3 Isabelle was named after four-year old Isabelle Andersen by tunnel builders CPB John Holland Dragados. Isabelle represented the families of the tunnelling workers.
TBM4 Maria was named after 19th century Aboriginal rights advocate Maria Lock.
Safety of customers is the number one priority. Tunnel safety measures include cross passages linking the twin tunnels and constant camera coverage. To find out more about tunnel safety in the Sydney Metro Northwest tunnels.
Cross passages link the twin tunnels every 240 metres