All five TBMs are now underground and at work excavating the 15.5km City and Southwest extension to the Sydney Metro in Australia. Supplied by Herrenknecht, the five machines include four double-shield TBMs, and a multi-mode machine for excavation under Sydney Harbour, a route that will require boring through a section of Harbour sediment. The specialised machine was the last to begin work, departing from its Barangaroo launch site on the south side of the Harbour in early August 2019.
In addition to the twin tunnels, the new Metro line includes six new underground stations: Crows Nest and Victoria Cross to the north of the Harbour, and Barangaroo, Martin Place, Pitt Street, and Waterloo to the south (Fig 1). The tunnels, stations and excavations works package for the project was won by a John Holland-CPB Contractors-Ghella JV in June 2017 at a contract value of AUD$2.8 billion. The contract also includes a launch portal at Marrickville and a temporary TBM retrieval shaft at Blues Point. Bechtel is the Delivery Management Partner for the client, Sydney Metro.