Chatswood dive site

The dive site is being used to launch two tunnel boring machines (TBMs).

About Chatswood dive site

The Chatswood drive site was established to support:

  • Operation of two tunnel boring machines
  • Construction of about 250 metres of new above-ground metro tracks and the realignment of the T1 North Shore Line
  • The fit-out of tunnel rail systems.

Work at the site includes:

  • Excavating and constructing the Chatswood dive structure and tunnel portal
  • Launching and supporting two TBMs
  • Supporting the realignment of the T1 North Shore Line between Chatswood Station and Brand Street, Artarmon to accommodate the new metro tracks
  • Supporting the construction of about 250 metres of new above-ground metro tracks
  • Supporting the fit-out of the tunnel rail systems
  • Installing rail dampers and deck absorption to provide mitigation for operational train noise
  • Constructing the tunnel portal
  • Constructing a fire protection wall along the entire length of the dive structure to provide separation between the two metro tracks.

Main site features

  • Laying around 250 metres of new track in the existing corridor between Chatswood Station and the dive site, in order to connect Sydney Metro City & Southwest to Sydney Metro Northwest and the T1 North Shore Line
  • Permanently closing the road bridge at Nelson Street, Chatswood
  • Realigning the T1 North Shore Line within the existing rail corridor between Chatswood Station and Brand Street, Artarmon
  • Constructing a new rail bridge for a section of the northbound track to pass over the metro northern dive structure
  • Removing the existing Sydney Trains maintenance access point from Hopetoun Avenue, Chatswood
  • Providing a new rail corridor access point from Brand Street, Artarmon.

Dive structures and tunnel portals

Two dive structures and tunnel portals were built, one at Chatswood and another at Marrickville. These sites, along with the Barangaroo Station site, formed the TBM launch sites and provided support for tunnelling operations including:

  • Spoil storage and removal
  • Pre–cast concrete ring segments storage
  • Work trains (or similar) to transport staff and materials to the cutting face
  • Water and power supply
  • 24–hour fresh air tunnel ventilation
  • Separation plant (Barangaroo only)
  • Grout batching plant
  • Drainage, water treatment and disposal
  • Material storage
  • Office facilities, work amenities and parking. 

More information about tunnelling at Sydney Metro can be found here.


The dive site is located south of Chatswood Station and north of Mowbray Road adjacent to the T1 North Shore Line at Chatswood. It borders the Pacific Highway, Mowbray Road and Nelson Street.

Construction updates

Monthly notification - Northern Connection - November 2020
PDF | 303.54 KB
Monthly notification - Northern Connection - October
PDF | 304.98 KB
Quarterly newsletter - Chatswood dive site - September 2020
PDF | 2.47 MB
Monthly update - Chatswood dive site - Sep-Oct 2020
PDF | 369.34 KB
Construction notification - Northern Connection - September
PDF | 301.68 KB

Artarmon power upgrade