The first look at the machines that will tunnel up to 50 meters below Sydney Harbour has been unveiled.

The NSW Government has released the first images of the tunnel boring machines (TBMs) that will be used on the $7.4 billion Western Harbour Tunnel project.

Set to open in 2028, the 6.5 km tunnel will create a new harbour crossing that will link northern, inner western and southern Sydney.

It will deliver twin tunnels that will connect to the M4-M5 Link at Rozelle and the Warringah Freeway at North Sydney. The tunnels will have three lanes in each direction.

The tunnel will connect to WestConnex at the Rozell Interchange. From there, it will cross underneath Sydney Harbour between Birchgrove and Waverton before connecting with the Warringah Freeway near North Sydney.

One complete, the project will take pressure off the corridors of the Sydney Harbour Bridge, Sydney Harbour Tunnel, Anzac Bridge and the Western Distributor.

Traffic on the Western Distributor, Sydney Harbour Tunnel and the Sydney Harbour Bridge will be reduced by 35 percent, 20 percent and 17 percent respectively.

The tunnel is being delivered in two stages.

The first stage involves includes construction of the 1.7km southern section of the tunnel connecting Emily Street in Rozelle to Cove Street in Birchgrove.

This stage is being delivered by John Holland and CPB Contractors. Works commenced in June 2022.

Tunnelling under the harbour will take place in the second stage.

This includes construction of the northern end of the tunnel, connections to the Warringah Freeway near North Sydney, tunnelling under Sydney Harbour and the complete tunnel fit-out.

This stage is being delivered by ACCIONA.

The $4.24 billion contract for this stage was signed in late 2022 before early works commenced in May 2023.

 

Largest machines in the Southern Hemisphere

Seen rolling off the assembly line, the machines are the largest TBMs to be constructed in the Southern Hemisphere.

Coming in at 4,350 tonnes in weight, each machine is 102 meters long and 15.7 meters in diameter.

The machines will work under Sydney Harbour between Birchgrove and Waverton at a depth of up to 50 meters below sea level.

They will excavate 1.5 kilometres of the twin motorway tunnels with three lanes in each direction.

The machines will be assembled in their launch chambers deep underground in Birchgrove with the help of a 500-tonne crane.

As the machines proceed, the tunnels will be lined and supported by around 13,0000 concrete segments. These will be precast in Western Sydney.

The TBMs are expected to take around a year to complete their work.

Once launched, tunnelling will be ongoing and will continue through all hours of the day and night.

As many as 40 people will be working on the machines at any one time. These will be some of the approximately 6,900 workers who are expected to be employed on the Western Harbour Tunnel project in total.

The TBM cutterheads are adorned with artwork to honour their namesakes – Aboriginal women Barangaroo and Patyegarang.

This will provide a tribute to Sydney’s past as the TBMs prepare to shape its future.

Minister for Roads Jenny Aitchison marvelled at the machines.

“These magnificent machines are going to deliver on the Future Sydney vision by carving out our second under-harbour road crossing,” Aitchison said.

“These are the largest TBMs in the Southern Hemisphere – which gives you a sense of the magnitude of this project that will revolutionise the way our city moves.

“Three whole Sydney Metro tunnels could fit within the diameter of the Western Harbour Tunnel, and each TBM is around the same weight as four Freshwater ferries.”

 

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