Yonge North Subway Extension
Extending Line 1 subway service nearly 8 km north from Finch Station to Richmond Hill.- Projects & Programs
- Yonge North Subway Extension
- What We're Building
- Tunnel launch shaft and portal
Tunnel launch shaft
The launch shaft will be temporary construction infrastructure that will serve as the starting point for the 6.3-kilometre journey of the future tunnel boring machines (TBMs).
It is a deep, reinforced excavation where the two TBMs will be assembled and lowered into the ground to start tunnelling.
Located south of the future Bridge Station, the launch shaft will allow the TBMs to begin their journey south to Finch Station, where they will be lifted out of the ground and retired once tunnelling is complete.
Local construction
Click the icons on the map for the latest construction notices and other related information.
Building the shaft involves installing strong concrete support walls to keep the excavation stable before removing soil in stages. After that, reinforced concrete is poured to form a sturdy slab that will support the TBMs.
The launch shaft site will be used to store construction equipment and materials needed for tunnelling, including the concrete segments that will be used to build the tunnel walls. Excavated soil and debris from the tunnel boring machines will travel along a conveyor system back to the shaft, where it will be collected and hauled away to be safely disposed.
From above: the launch shaft site for the Eglinton Crosstown West Extension served as a hub for tunnelling. The Yonge North Subway Extension will use a similar approach.
Tunnel portal
After tunnelling is complete, the launch shaft site will be converted into the tunnel portal — the permanent structure where Line 1 subway trains will enter and exit the underground tunnels.
The portal will be built on the same footprint as the launch shaft but is finished in a very different way. The temporary shaft infrastructure will be removed before permanent reinforced concrete foundations and walls are installed, followed by waterproofing and drainage systems. These will keep the tunnels dry and stable, and make sure subway trains move safely between the surface and tunnels.
A tunnel portal under construction for the Eglinton Crosstown West Extension.
Get in touch
We're committed to keeping you informed and engaged every step of the way as we build the Yonge North Subway Extension.
Our team is here to answer your questions, address issues, and provide the information you need. Reach out to us any time at YongeSubwayExt@metrolinx.com or 416-202-7000.
You can also book a meeting with us online or at our community office in York Region.
