The first of two machines which will tunnel underneath the Brisbane River and CBD is almost ready as work to prepare for the commencement of tunnelling on what will be Brisbane’s largest rail project in decades continues.

Queensland Minister for Transport and Main Roads Mark Bailey said that the first of two tunnel boring machines (TBMs) that will construct two 5.9 kilometre tunnels as part of the $6.9 billion Cross River Rail Tunnel project is almost ready and will undergo final checks next week.

The second TBM will undergo a similar process next month.

Set to open in 2024, the Cross River Rail project will link Bowen Hills to the north of the Brisbane CBD and Dutton Park south of the Brisbane River via 10.2 kilometres of dual track (see map below).

This will include 5.9 kilometres of tunnelling under the river and the CBD along with four new underground stations at Boggo Road, Woolloongabba, Albert Street and Roma Street.

The new line will relieve congestion on a rail network which is expected to see a tripling in demand for passenger services between now and 2036 amid population growth in South-East Queensland along with employment growth in metropolitan Brisbane.

The line will remove a bottleneck at the core of the rail network which currently sees every train go across a single river crossing.

Whilst the cost of the project is often quoted at $5.4 billion, it’s actual cost according to the 2019 Queensland State Budget is $6.9 billion – $5.4 billion of which will be financed by the Queensland Government along with $1.48 billion in private finance contributions.

Each tunnel boring machine will be 165 meters long and will weigh around 1,350 tonnes.

After commencing at the Woolongabba station site early next year, the TBMs will tunnel under the Brisbane River to Albert Street station in mid-2021 before continuing to the new Roma Street station and emerging at the project’s northern portal at Normanby.

Whilst making their way through hard rock, the TBMs will also install 4.2 tonne precast concrete to line the tunnels.

TBM Facts:

• Two TBMs are being refitted and refurbished from use on the Sydney Metro project in NSW at Herrenknecht’s northside facility
• More than 100 local companies have been supporting Herrenknecht to prepare the TBMs, including QIC Protective Coatings (Birkdale), LCR Group (Wacol), AC Hargreaves Pty Ltd (Seventeen Mile Rocks), C&L Tool Centre (Hendra), ShapeCUT (Carole Park), and Citi-steel (Darra)
• More than 40 workers have helped refurbish the two TBMs’ gantries, assembling their shields and testing all their systems to make sure they’re ready to go
• The TBMs’ back-up gantries have been repurposed from the Sydney Metro project
• Each TBM weighs 1350 tonnes and is 165 metres long
• A crew of up to 15 people will work in a TBM at any one time
• The cutterhead weighs 106 tonnes and measures 7.2 metres in diameter
• It includes 39 cutting discs that exert up to 32 tonnes of pressure each
• TBMs will work at a rate of 20 to 30 metres per day
• At their deepest point, the tunnels will be 58m below the surface at Kangaroo Point and 42m below the Brisbane River
• Each TBM is fully equipped with crew facilities, offices and toilets
• The TBMs must be disassembled to be transported
• The TBMs will generate 290,000 cubic metres of spoil as they make way for the twin Cross River Rail tunnels.