Work has started on construction of four machines - set to weigh more than 900 tonnes each - which will plough through an average of 120 metres of sandstone per week as they deliver the longest rail tunnels ever to be built in Australia.

In a joint statement with Transport Minister Gladys Berejiklian, state Premier Barry O’Farrell says the custom-made tunnel boring machines (TBMs) which will deliver two fifteen-kilometre twin tunnels as part of Sydney’s $8.3 billion North West Rail Link had been ordered and were now being prepared.

“The North West Rail Link is the biggest public transport infrastructure project in Sydney since the Harbour Bridge almost a century ago,” O’Farrell said. “The first tunnel boring machine will be in the ground next year and the three others will follow soon after.”

Set to be designed and built in France by French manufacturer NFM Technologies, the machines will cut the 15-kilometre tunnels – set to become Australia’s longest – between Bella Vista and Epping.

The machines will be made from components sourced from across Europe which will be designed and pre-assembled in France before being sent to China where steel structures like cutter heads and back up trailers will be made.

After they have been assembled overseas, the machines will be pulled apart and shipped to Australia where they will take around eight weeks to assemble.

Once in use, the TBMs will use as much around 400 times as much power as an average house to plough through 29 kilometres of conveyor belts to remove the crushed rock from deep underground – the distance from the Sydney CBD to Blacktown.

North West Rail Link Map

Berejiklian says simply getting the machines into Sydney – most likely in the middle of the night to minimise traffic disturbance and under escort – will be a significant logistical task in itself, with the TBM parts expected to be shipped to Port Botany and the cutter heads slated to be shipped separately to either the Port of Newcastle or Port Kembla where they will then be transported to Sydney on the back of a heavy lift semi-trailer.

Set to connect the northern suburbs of Rose Hill and Epping via Castle Hill, the North West Rail Link is a 23-kilometre project which includes 15 kilometres of underground tunnel, a four-kilometre skytrain viaduct and upgrades of the existing Epping to Chatswood Link, as well as eight new stations and 4,000 commuter underground car parks.

The government says the project will provide faster and more reliable travel compared to current bus routes and will allow for more trains between Epping and Chatswood.

A joint venture involving Leighton subsidiaries Thiess and John Holland together with Spanish firm Dragados was awarded the contract to construct the tunnels and excavate the new underground stations in June.

The link is set to open by the end of 2019.

Berejiklian says the arrival of the machines next year will be an exciting to time for the city.

“Of course, when the time comes next year we will keep the community fully informed – and we even expect to see some people lining the streets to get a glimpse of the remarkable machinery which is turning the North West Rail Link into a reality,” she said.