How Cross River Rail is building twin tunnels under the Brisbane River

Exclusive video: An engineering miracle is happening right under the feet of people in Brisbane as the Cross River Rail tunnels make their way under the river.

It’s the engineering miracle happening right under our feet.

Thousands of concrete segments are being meticulously installed inside the $5.4 billion Cross River Rail tunnel as it makes its way under the Brisbane River.

The concrete segments, produced out of the Wagners Precast facility at Wacol, are loaded on to two massive tunnel boring machines (TBMs) and then configured into rings to line the tunnel wall as the machines move through.

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More than half of the 25,000 concrete segments needed to line the twin tunnels beneath the river and CBD have been produced.

The first of the two giant TBMs excavating the tunnels carved its way beneath the river in the past week, and is moving northwards under the CBD.

Cross River Rail workers Alena Conrads and Francesco Anghetti inspect the concrete rings. Picture: Peter Wallis

Cross River Rail Delivery Authority’s area engineering manager for Woolloongabba and tunnels, Tai Luong, said each ring was made up of six segments.

They are being stored at the Wacol facility, before being transported to Cross River Rail’s Woolloongabba site, where they undergo rigorous checking for cracks, defects and to ensure they fit as perfect rings.

When you’re building the city’s first under river rail crossing, it’s critical.

“Around the perimeter of each of the segments is a waterproofing membrane, or gasket, and that touches on each of the segments,” Mr Luong said.

“When the (boring) machine pushes off the segment, it compresses the gasket to ensure it’s waterproof.”

Cross River Rail’s tunnel boring machine. Picture: Peter Wallis

Wagners Precast facility at Wacol – one of 800 local suppliers and subcontractors to benefit from the project so far – has manufactured more than 14,000 segments to date.

More than 105,000 cubic metres of concrete will be used to create the segments.

There are currently more than 2400 people working on Cross River Rail’s 12 active sites, including Albert and Roma streets, Boggo Rd and Woolloongabba.

They include engineers, designers, architects, project managers, apprentices and professionals.

Alena Conrads and Francesco Anghetti with the concrete segments. Picture: Peter Wallis

Transport Minister Mark Bailey said the project represented an opportunity for a diverse range of skills.

“Not only does the breadth of Cross River Rail’s construction requirements ensure that people across hundreds of different trades remain gainfully employed, it presents an opportunity for Queenslanders to stay home and to work on a project that will benefit their home state directly,” he said.

Originally published as How Cross River Rail is building twin tunnels under the Brisbane River