Infographic depicting a cross section, with a property on the surface and the tunnel below. An arrow and value indicates the depth of the tunnel below the property, and another arrow and value indicate the surface distance from the property to the tunnel.

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Tunnel tool

The tunnel boring machine (TBM) tunnelling works for the Southern Tunnels are planned to start in 2026. Check back here for updates.

Using this tool

Zoom in on an area of interest within the T2D Project corridor
Click on a property highlighted within the T2D corridor to see the depth of the nearest tunnel
Turn map layers off and on in the drop-down menu next to the search bar in the map window

OR

Search for an address. Tunnel depth information is indicative and only available for properties within the T2D Project corridor.

Watch the video to get an overview of the tunnels and motorway design

About the tunnel boring machine

The T2D Project will have three 15m diameter TBMs working concurrently so that the Southern and Northern Tunnels can be constructed at the same time. There will also be two smaller 4m diameter mini TBMs that will excavate the cross passages between the main tunnels.

These cross passages are located every 120m and house equipment which support the day-to-day operations of the tunnels. They also form part of the tunnel safety system, allowing access for tunnel and emergency service personnel as needed.

Tunnel depths

Depth shown is indicative and may vary due to ground conditions and detailed design.

Depth measurements have been calculated from the property boundary to the tunnel roof.