Westmead metro station cavern formwork the biggest in the southern hemisphere

In a tightly coordinated 82-hour operation, crews jacked and winched the temporary arch into position with millimetres to spare. Once the structure was in place, the team completed a 1,941-tonne concrete pour to create the cavern’s 2.5-metre-thick walls.  

It took almost 12 months of careful planning and collaboration – along with multiple crawler cranes - to construct the huge structure that reaches 21 metres high, equivalent to a seven-storey building.  

With the formwork operation now complete, the tallest cavern on the Sydney Metro network is fully lined, standing around 26 metres high.   

Crews are now retrieving the 1,200-tonne Tunnel Boring Machines (TBMs) that arrived beneath Westmead in September and October, lifting each machine out in sections through an opening in the roof of the acoustic shed built over the station cavern.   

Meanwhile, tunnelling at the eastern end is approaching its final breakthrough to Hunter Street in Sydney’s CBD, with TBMs Ruby and Jessie now less than 550 metres from completing the 24-kilometre twin tunnels.