They are the massive machines that will help build new subways in the GTHA. This week, Between the Lines: A Metrolinx Podcast digs into tunnel boring machines and how they work. Listen to the full episode below.
This week, the Metrolinx podcast team is going deep on the mechanical marvels that are tunnel boring machines (TBM).
Want to learn more about the podcast? Check out the new show landing page.
Host Matt Llewellyn speaks with Walter Trisi, director of construction for the Scarborough Subway Extension project. With Trisi’s decades of tunnelling experience on hand, the two chat about how a tunnel boring machine works, how using TBMs actually minimizes disruptions to the surface and how the Scarborough Subway Extension is making history in Ontario.

Episode 17 – Fifty Years in Rail: Talking GO Transit's past & future with Rob Fuller – Between The Lines: A Metrolinx Podcast
- Episode 17 – Fifty Years in Rail: Talking GO Transit's past & future with Rob Fuller
- Episode 16 – #AMAwithAMA – Who is Train Guy, can TBMs be reused and more!
- Episode 15 – Tunnel Boring Machines
- Episode 14 – #AMAwithAMA – Your Light Rail Transit (LRT) questions answered
- Episode 13 – Navigating market volatility in transit
Do you have a question you’d like answered? Email the team at podcast@metrolinx.com.
Read more about the three TBMs currently in use by Metrolinx and how the public helped named them here.

Also, tunneling recently started on the Eglinton Crosstown West Extension – learn more here.
To learn more about the Scarborough Subway Extension, click here.
You can also watch how the Eglinton Crosstown LRT was tunneled below:
Story by James Wattie, producer/editor, Between the Lines: A Metrolinx Podcast