First tunnel borers launched on Sydney Metro West scheme

Nov 06, 2023

The Acciona and Ferrovial joint venture has launched the first two tunnel boring machines to build a section of the 24km Sydney Metro West line in New South Wales, Australia.

The Acciona and Ferrovial joint venture (JV) has begun major tunnelling works on the New South Wales Government's Sydney Metro West project, a new underground railway that will connect Greater Parramatta and the Sydney central business district (CBD). The JV was awarded the A$1.96bn (£1bn) central tunnelling contract on the scheme in July 2021.

The Herrenknecht tunnel boring machines (TBMs) arrived at the Bays Station site, which is in a new precinct 2km west of the Sydney CBD, in October of last year.

The first TBM, dubbed Daphne, has already dug 150m of its 11km drive from the Bays to the Sydney Olympic Park, while TBM Beatrice is 45m into its journey on the parallel tunnel. They are expected to excavate an average of 200m per week and to finish tunnelling in late 2024.

TBM Daphne has been named in honour of Paralympic sport pioneer Daphne Hilton, who was one of the most successful Australian athletes of all time and a trailblazer for women in sport. TBM Beatrice's namesake is local newspaper seller Beatrice Bush, who sold newspapers for more than 25 years from the traffic island at the intersection of Victoria Road and the Crescent in White Bay.

The two TBMs, which are the first ones in the ground for the project, include refurbished parts from the boring machines used on the Sydney Metro City & Southwest project. The cutterheads, front shields and gripper shields were originally used for the TBMs that dug the metro tunnels from Chatswood to Blues Point.

Each TBM is approximately 7m in diameter, 165m long, and weighs almost 1,300t.

Work on cross passages and crossover caverns will also progress, while the TBMs continue their excavation.

The project's western tunnelling contract, covering 9km of rail tunnels between Sydney Olympic Park and Westmead, was awarded to a Gamuda and Laing O’Rourke Australia JV in March 2022.

A John Holland, CPB Contractors and Ghella JV won the 3.5km eastern tunnelling contract between the Bays and Hunter Street in Sydney's CBD in November of last year.

In related news, two out of a total of three roadheaders have started digging tunnels that will connect the Sydney Metro West line to a new stabling and maintenance facility at Clyde.

The 120t, 4.8m high and 4.5m wide machines were lowered into a temporary access shaft at Clyde, which is approximately 28m below the surface. A 750t mobile crane then carefully lowered each roadheader into the shaft in pieces, with the heaviest load weighing just over 92t. It then took two days to assemble each machine.

The final roadheader will soon be assembled to help excavate the tunnels and two junction caverns that will allow trains to move from the underground railway tunnels to be stabled and undergo routine maintenance as required.

It will take around 13 months for the roadheaders to excavate the tunnels and junction caverns.

Sydney Metro West aims to double the rail capacity between Sydney's two biggest CBDs once passenger services commence in 2030.

Earlier this year, New South Wales premier Chris Minns said that the full Sydney Metro programme needed to undergo a major review due to cost overruns and delays. The final report is expected by the end of this year.

The Guardian recently reported that the overall scheme was already A$21bn (£11bn) over budget, and Sydney Metro West had gone over its initial estimates by A$12bn (£6.4bn) to A$25.32bn (£13.44bn).

The Sydney Metro is Australia's biggest public transport project and includes three schemes. In addition to Sydney Metro West, these are City & Southwest and Western Sydney Airport. As a result of the project, by end of 2030, Sydney is expected to have 113km of new metro rail.

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