Sydney’s Mega-Sized Metro

If you’re going to undertake a megabuild you need some huge kit and the tunnel boring machines (TBMs) being used to build large chunks of Sydney’s new Metro certainly fit the bill.

There are five of the individually named 975-tonne borers digging from Marrickville to Chatswood and under the harbour and they are churning up plenty of rock.

The good news is much of the rock is being recycled and being used to build another massive infrastructure project – Sydney’s second airport (Nancy Bird-Walton airport). In fact, more than 500,000 tonnes of sandstone will be transported from Metro tunnelling sites at Chatswood and Marrickville to the Western Sydney International site.

Over 148,000 tonnes of sandstone has already been transported to the airport site since May with the aim of reusing 100 per cent of the excavated crushed rock from the 15.5-kilometre twin tunnels being dug between Chatswood and Marrickville.

Image Credit: Sydney Metro

As for the names of the borers, TBM Kathleen who has just begun her journey under the harbour is named after Kathleen Butler, who played a vital role in the construction of the Sydney Harbour Bridge as the technical advisor to legendary engineer John JJC Bradfield.

Now while the numbers for the rock and the length of the tunnel are impressive, they pale in comparison to the overall cost which is slated to rise above $20 billion by the time the whole project comes online in 2024.

Yet, while most hapless Sydney commuters have a while to wait, the already operating North West Metro line has opened up a large swathe of the city’s north-west to better public transport.

Image Credit: Sydney Metro

According to New South Wales Transport Minister Andrew Constance the project’s impact on the city is comparable to that of the Sydney Harbour Bridge.

An example of this impact is the Sydney Metro Northwest line which is expected to reduce car trips by more than 14 million a year – or 12,000 fewer car trips in an average two-hour weekday morning peak according to the state government.

Beyond getting cars off the road, Sydney Metro also promises an air-conditioned metro train every four minutes in the peak, improved CCTV and surveillance, new or upgraded concourses, all trains stopping at local stations, reduced travel time and direct services to Martin Place, Barangaroo, North Sydney, Chatswood, and Macquarie Park.

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