Sydney, NSW, Australia

Sydney Metro City & Southwest

Transport for New South Wales


Sydney Metro City & Southwest is the second of five phases in Australia’s largest public transport project to date. This phase extends Sydney’s new metro rail network from the end of Sydney Metro Northwest at Chatswood, under Sydney Harbour, through the Central Business District (CBD), and west to Bankstown. 

The project includes new twin 15.5‑kilometer (9.6 mi) tunnels. At the completion of the project, Sydney will have 31 metro stations and 66 kilometers (41 mi) of stand-alone metro railway, which will revolutionize the way Australia’s largest city travels. 

Fast Facts
  • Twin 15.5-kilometer (9.6 mi) tunnels
  • Underground station
  • Temporary retrieval shaft

Scope of Work

Delve Underground was involved in the project from the start of its tender phase. We were engaged by the Design and Construct (Design-Build) Contractor John Holland, CPB Contractors and Ghella JV (JHCPBG) to deliver designs for the Pitt Street Station and Blues Point Shaft sites, as well as to provide construction phase support. 

Challenges & Innovations

Pitt Street Station is located beneath major streets in Sydney’s busy CBD. Tunneling occurred at relatively shallow depths with little competent rock cover. The station geometry also required excavation within 3 meters (10 ft), in plan, of existing high-rise structures. For an added challenge, the station invert was designed to be just above the installed permanent rock bolt support of an active motorway tunnel. Excavation of the station followed the sequential excavation method (SEM).

Blues Point Shaft, located on the northern shore of Sydney Harbour, was designed as a temporary shaft for the retrieval of two hard rock tunnel boring machines (TBMs) and one under-harbor TBM, to be recovered twice. Excavation of the shaft also employed the SEM methodology and utilized rock bolts and steel fiber reinforced shotcrete.