Sydney Metro Harbour tunnel

Tunnelling

Sydney Metro City & Southwest

Tunnelling finished in March 2020 on the twin tunnels from Chatswood to Sydenham, including under Sydney Harbour and through the Sydney CBD.

The tunnel boring machines (TBM) tracker used to follow the historic dig by the five tunnel boring machines on the City & Southwest project can be found on this map.

Sydney Metro West

The tender process has started for tunnelling between Westmead and The Bays precinct with the first tunnel boring machine expected to be in the ground before the end of 2022.

About our tunnels

Sydney tunnel depths

Marrickville cutterhead lift

Barangaroo TBM cutterhead

Barangaroo TBM Mum Shirl Cutterhead Lift

TBM Mum Shirl being lifted

Victoria Cross breakthrough

Chatswood dive tunnels

Diagram showing specialised tunnel boring machine.

Specialised TBM used to cross the Sydney Harbour

TBM Kathleen barge move

Our tunnel boring machines

Five TBMs were used to deliver the tunnels between Chatswood and Sydenham for Sydney Metro City & Southwest. This included 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 Metro North West Line. 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.

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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.

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.

TBM4 Mabel was named after Mabel Newill, a matron at Royal Prince Alfred Hospital - she helped stop the spread of typhoid in Sydney, in the early 1900s.

TBM5 Kathleen was named after Kathleen Butler, who worked on the Sydney Harbour Bridge – technical advisor to legendary engineer John Bradfield – a century ago.

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 breakthrough at Showground

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.