Australia’s New South Wales (NSW) Government has announced the start of work on the second Sydney Harbour rail crossing.
As part of this, geotechnical drilling is expected to start up to 70m below the harbour in the coming weeks to decide the location for the rapid transit railway tunnels.
Transport and infrastructure minister Andrew Constance said: "Sydney Rapid Transit will turn the city’s crush hour into Sydney’s rush hour.
"From the end of the North West Rail Link at Chatswood, Sydney’s new rapid transit network will continue under Sydney Harbour, through new railway stations in the CBD and west to Bankstown with capacity for trains to run every two minutes."
The Sydney Rapid Transit geotechnical programme will see the drilling of approximately 30 boreholes, almost half of them will be beneath Sydney Harbour and the rest on land either side along the route.
It will help to determine the ground conditions for tunnelling, ensuring the strength of the underlying rock and groundwater conditions.
The holes will be filled with cement to create a permanent seal after the drilling work under the harbour is finished.
NSW premier Mike Baird said: "This new rail crossing of Sydney Harbour is the key to increasing capacity on our rail network by 60%, allowing us to move an extra 100,000 people every hour right across Sydney."
The geotechnical drilling is also set to be carried out at Sydenham, in the Sydney CBD, North Sydney, Crows Nest and Artarmon.