Two roadheader tunnelling machines are now working underground at Sydney Metro’s Martin Place Station site.
Tunnelling work is taking placed around the clock 18 metres below Castlereagh and Elizabeth streets.
The 130-tonne roadheaders are on track to finish the underground station caverns before two tunnel boring machines reach the site next year.
About 52,500 tonnes of crushed rock has been removed from the site; all of it is being re-used, including at the new Sydney Metro site at Barangaroo.
The excavated station cavern walls are supported with 2950 rock bolts set with 37,000 litres of grout and 1,200 cubic metres of sprayed concrete.