Sydney Metro’s Tunnel Boring Machine (TBM) Kathleen has begun tunnelling for the historic first rail crossing deep under Sydney Harbour.
The TBM has already tunnelled the first 100m of its 1km journey 30m underneath the harbour.
Once the first tunnel is complete, Kathleen will then build the second tunnel under Sydney Harbour before being retrieved at Blues Point and taken away by barge.
The machine is expected to tunnel through clay, silt and sediment, and will use state-of-the-art tunnelling technology to safely make its way under the harbour.
Four TBMs have already completed over half of the 31km of tunnel for Sydney Metro City and Southwest.
This specialised TBM is named after Kathleen Butler, who played a vital role in the construction of the Sydney Harbour Bridge as the technical advisor to legendary engineer John JJC Bradfield.
It is expected to take TBM Kathleen about four months to complete her first tunnel.
Together, all five TBMs will deliver twin 15.5km rail tunnels for Australia’s biggest public transport project.