File:Sydney Metro First harbour tunnel breakthrough

Description
This is what happens when a mega borer that’s built a 1km tunnel deep under Sydney Harbour reaches the other side.

The first of two metro railway tunnels deep under Sydney Harbour has been completed in an historic milestone for public transport in Sydney.

At their deepest point, the tunnels are 40 metres beneath sea level.

Tunnel boring machine (TBM) Kathleen is building the twin railway tunnels.

The specialised under-harbour tunnelling machine launched in June from the new Barangaroo Station site and took almost four months to tunnel nearly one kilometre to the northern side of the harbour at Blues Point.