North Sydney, New South Wales can be divided into three periods – the first from the original opening in 1886 to 1909, when the McMahons Point line opened. The second period covers the time until the Wynyard line was opened across the Sydney Harbour Bridge in 1932, and the third until construction of the Cahill Expressway on the eastern side of Sydney Harbour Bridge and the wider closure of the system in 1962. The first part of the North Sydney tramway system was a double-track cable tramway which commenced at the original Milsons Point Ferry wharf, located where the north pylon of the Harbour Bridge
Sydney Harbour Tunnel South) to the Sydney Harbour Bridge, which has eight lanes, with a tidal flow operation. In 2008, the tunnel was carrying around 90,000 vehicles per day. The tunnel is made up of three sections: twin land tunnels on the north shore, twin land tunnels on the south shore and a immersed tube (IMT) structure. The tunnel falls about from the northern entrance and about from the southern entrance to its deepest point, below sea level. The IMT structure consists of eight precast concrete units. The units were constructed over away in a casting basin at Port Kembla and then towed