The area surrounding Exhibition Station looks quite a bit different to CNE attendees this summer as Metrolinx prepares the site to become the new tunnel launch point for the forthcoming Ontario Line subway.

Work on the new 15.6-km subway line connecting Exhibition Place with the recently-shuttered Ontario Science Centre is well underway, and will soon forge ahead with the first new subway tunnel constructed in the city centre since the first leg of Line 1's University subway stretch was completed in 1963.

Before tunnelling can begin for the six-kilometre central stretch of the 15-station line, crews must prepare a tunnel launch shaft, now in progress at the east end of Exhibition Station.

Metrolinx has shared a new update on the current piling stage of construction, prepping a launch shaft from which the twin tunnel boring machines will etch their way eastbound to the tunnel's terminus at the planned Don Yard portal, just west of the Don River.

We're getting ready to dig the first subway tunnel under Toronto's downtown core in over 60 years for the future Ontario Line. But first, we need a launch shaft! Watch to learn more about this exciting work taking place at Exhibition Station. pic.twitter.com/PcTtSB3SLU

— Ontario Line (@OntarioLine) August 16, 2024

Crews are now drilling deep into the soil around the launch shaft site, being constructed immediately south of Liberty Village, next to the Toronto Police Traffic Services building, between King West Laneway and Hanna Avenue.

Current activity involves the drilling of secant or tangent piles that will form stable underground walls that will contain the excavation to come.

Once piling is complete and this massive pit is dug, tunnel boring machines will next be lowered into the void to begin their journey eastward, carving out the first new subway tunnel in the city centre since 1963 — a year that saw JFK assassinated and still six whole years before the first moon landing.

Unlike your standard tunnel launch shaft, this large excavated trench will eventually be converted into a portal linking the tunnel's west end with the short surface section leading into the Ontario Line's western terminus at Exhibition Station.

This follows a similar model as the eastern extraction shaft dug for the Eglinton Crosstown LRT's tunnels a decade earlier, which now act as the portal between the line's central tunnel and eastern surface section.

The current piling phase is expected to continue until at least the end of November 2024, to be followed by excavation of the launch shaft.

Metrolinx expects the portal structure to be completed in 2025 or 2026, which will be followed by the insertion of TBMs and the start of the eastbound tunnelling process.