New Road tunnel under Northbridge

You may have read in Thursday’s (16-Mar-2017) papers that the NSW government announced that a new road tunnel would be built linking Seaforth with the Gore Hill and Warringah expressways. (see: http://www.smh.com.au/nsw/berejiklian-commits-to-balgowlah-to-warringah-freeway-tolled-tunnel-20170316-guzdqo.html

Little detail was provided with the announcement, but an indicative route has been published that shows it running under Northbridge and coming up at Artarmon to connect with the Gore Hill Freeway. Geo-surveying is to be carried out to determine the actual route of the tunnel in 2017 and 2018.

Using the available information and Google Earth, Artarmon Progress Association has prepared a couple of images to show the anticipated route. The more detailed image (above) shows the anticipated route through Willoughby and Artarmon. At this early stage, it looks like it will possibly cut through the southern end of Artarmon Reserve.

At this stage guesstimates have been used to prepare these images, it is our best assessment using the limited information we have.

It is likely that part of Artarmon Reserve, all of Artarmon Park, and the Artarmon apartment buildings immediately north of the motorway will be lost to the motorway. Also the temporary school site.

The Artarmon Industrial area will get it second stack – likely in the corner near the rail line (across the track from Narremburn).

The picture above shows an “Alternate Northern Sydney motorway link” as proposed by Artarmon resident, Peter Egan. In red are suggestions to improve cross-harbour and northern Sydney motorway links. In Blue is the govt plan. In Yellow are the orbital motorway and other roads.

The name of the game in road planning is to form a grid to minimise journey times and congestion.

The government plan has a gigantic interchange at Cammeray where all the traffic north of the harbour, and east of Macquarie Park, will split into Harbour Bridge, Harbour Tunnel and Western Harbour Tunnel. An accident here could bring the Australian economy to a halt.

For more information, see the RMS Western Harbour Tunnel and Beaches Link to project website at:

The government has announced that houses in Artarmon and Cammeray will be compulsorily acquired as part of this project and that affected property owners will be contacted. We are anxious to know which properties will be affected by this project. This will provide us with a better understanding of the planned route and impact.

Please let us know if you, or someone you know, is contacted by the NSW Government about this tunnel.

Note: The content of the above post was originally prepared by Peter Egan (Artarmon PA) with other material supplied via email broadcast by Bob Taffel (South Willoughby PA).


Northbridge 202 Facebook Update: 19-March-2017:

Starting in April up to 235 Borehole sites will start to appear around North Sydney, Cammeray, Artarmon, Willoughby, Northbridge, Seaforth, Balgowlah and other suburbs. While this is Geotechnical Work and may not foreshadow the final route of the Tunnel, it could certainly give Residents a ‘sneak peek’. If Locals, Residents and other communities could pass on sightings via a PM, we could start mapping out a possible path.


Update by Northbridge Resident – Matt Judson: 20-March-2017

Tunnel Depth

The quotes from the news say they will be drilling the borehole test size up to 150m in depth. The below graphic which was used to explain this for the Northconex Project (the tunnel from Beecroft to Hornsby which is over nearly 9km’s).

This Tunnel would be at least 7km – I’ve used Google Maps to ascertain this, but that is in a straight line, these boring machines work best and quickest that way – in a straight line. More on the Boring Machine next.

Boring Machines.

They can be up to 140+ meters long – hence they go best in straight lines. Once underground they can operate 24/7. What they call the dive sites for these are very large – one of the ones for the M1 was over 400 meters long, and 14 odd homes were compulsory acquired. The number of homes mentioned to be acquired which stands at 71 seems to match this sort of size for 2 dive sites at least. I heard Gladys speaking at a Function yesterday and in her words ‘there will be more to come’, and she acknowledge that the Tunnel would probably go under her house

Exhaust Stack or Ventilation Outlets (which is the preferred name).

This may be the most worrying thing for Northbridge – one of these. If there was to be one it may be placed at Clive Park or another reserve, so the Government doesn’t have to Aquire a Property or 2. Below is one of the M5 ones which Residents have long complained about including health problems.

Thanks Matt!


Received via email from the Commissioner, Warringah Inquiry 1982/3 –

There are moves afoot to revive the Freeway proposal dealt with in the Warringah Freeway Corridor Inquiry 1983.
Though the proposal is different, in that a tunnel is proposed, it nonetheless must be monitored closely. Fundamentally, what is proposed has little to do with traffic and everything to do with giving the impression of addressing the issue of congestion but, in reality, removing the one inhibition on the development of Warringah.
Such development will inevitably take green space and worsen congestion.

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