Huge void carved below Toronto intersection will soon be a subway station

The $27 billion Ontario Line is shaping up to be a generational transit improvement, and while it's still a long road ahead to an anticipated 2031 completion date, some of the line's future underground stations are already beginning to resemble their final forms.

Primed as the solution to Toronto's subway congestion woes, the 15-station, 15.6-kilometre line will link Exhibition Place in the southwest to Don Mills and Eglinton in the northeast, including a central tunnelled section through the heart of downtown.

Crews are working away at the central tunnelled stretch, which includes underground stations at King/Bathurst, Queen/Spadina, Osgoode, Queen, Moss Park, and Corktown.

Osgoode Station — connecting passengers with the existing Line 1 station of the same name — is among the stations being formed through underground mining operations, carving away space to accommodate future station platforms.

The station works include a pair of excavation shafts at the northeast corner of Queen and University and the southeast corner of Queen and Simcoe.

Excavation shaft for Osgoode Station.

Deep underground between the two excavation shafts flanking the future station, a spacious cavern is growing wider and deeper as crews continue the sequential excavation process.

Cavern at Osgoode Station site.

Diagrams of the ongoing excavation show the current cavern size of roughly 11.3 metres high, shown shaded in light green. The darker green areas of the diagram show sections of the cavern to be excavated during this third stage of the sequential process.

The orange-shaded areas below show the upcoming stages that will bring the cavern to its final size, setting the stage for the arrival of tunnel boring machines and construction of the station platforms.

Crews are currently working in continuous shifts, 24 hours a day, 7 days a week, with the job expected to wrap up in Spring 2026.

Once fully excavated, the cavern will be prepped for the breakthrough of the twin tunnel boring machines — recently dubbed Libby and Corkie.

Work on the Ontario Line is expected to wrap up in 2031. The line has long been planned as a relief valve for overcrowded interchange stations like Bloor-Yonge by offering riders further to the east a direct link in and out of the downtown core.