Track-laying and construction of the new underground station to service Sydney CBD is set to commence, with the metro caverns now complete at Martin Place.
It took nearly two years to excavate and build the mammoth caverns that will house the metro platforms.
The caverns under Castlereagh and Elizabeth Street are each 28m below street level at Martin Place, are 220m long and 14m wide.
Excavation was completed ahead of the arrival of the first tunnel boring machine (TBM), TBM Nancy on 11 October 2019. TBM Mum Shirl was not far behind, breaking through into the cavern on 23 October 2019.
About 126,000 tonnes of rock was excavated from the two caverns and more than 5,500 tonnes of steel installed.
The smooth finished lining of the caverns required more than 21,500 tonnes of concrete.
Nine tunnels have also been built to connect commuters to the new station entrances as well as to the end of the platforms at the existing Martin Place Station.