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The Ontario Line is the biggest and most expensive rapid transit project in Canada’s history — for more basics on the project check out our previous article here — and while the Ontario government initially promised us an opening in 2027 and a low price for what we were getting — sadly, neither promise came to pass — significant progress is clearly visible across the line. In today's article we’d like to take you on a tour of the project and its infrastructure as it stands in late 2024. While nothing looks as close to finished as the Eglinton Line 5 Crosstown and Finch West Line 6 LRTs clearly do, it does very much feel and look like Ontario Line 3 is now “happening”.
North
Progress on the northern end of the line from [Insert-Name-That-Isn’t-Science-Centre] station south through Flemingdon Park and Thorncliffe Park has mostly been slower than the rest of the line. This is in large part because the stations in this section are all relatively simple “SkyTrain” style elevated structures, connected up by what will mostly be a segmental guideway that can be rapidly constructed in months, as opposed to years, meaning there is less time pressure to get work underway quickly.
That being said, the beginnings of work, and preparation works for the line are definitely visible. For example, HONI (Hydro One Network Infrastructure) is relocating high voltage transmission lines in the Don Valley around where the line will pass.
Vegetation has also been cleared and ground levelled to prepare for the construction of the two major bridges which will carry the line across upper sections of the valley. Note I mention two bridges because the second bridge crossing just south of the Ontario Science Centre will be much larger than most people probably imagine, and will also be uniquely horizontally curved.
Preparation along the DVP across the Don Valley
Of course, the star of the northern section of the Ontario Line is the giant bridge that will cross the main Don Valley and the Don Valley Parkway, giving motorists yet another view of subway trains passing high above. This bridge will be a balanced cantilever design, with the bridge deck built from the huge support towers outwards in what will be a very visually impressive feat, on what will otherwise be a rather plain bridge.
Fortunately, the bridge does score some points for intrigue in that it will seamlessly flow into the guideway through Thorncliffe Park on the north end, and into a portal connecting the line's northern tunnel at the south end, preparation works for which have already begun.
A little further to the south along the northern tunnel - which runs from the Don Valley to the new station at Gerrard and Carlaw with two underground stations, work is progressing on the Sammon Avenue emergency exit shaft. There are fewer emergency exits on the Ontario Line than some previous Toronto rapid transit projects because many sections of the line which would otherwise be too long to go without had they been fully underground, are broken up into tunnel and above ground sections. Site clearing is also progressing for Cosburn station and the future Danforth Line 2 interchange station at Pape.
East
Continuing south to the Ontario Line's most interesting section, we have the joint GO Ontario line corridor, running from Pape Avenue all the way to the tunnel portal at the east end of the downtown tunnel just south of the Distillery District.
To be clear, the character of the joint corridor changes along its length, in the northern sections the Ontario Line will share space on a newly enlarged and rebuilt embankment with the Lakeshore East and Kitchener-Stouffville GO lines (and yes, the all-too-odd VIA train), while to the south, the Ontario Line ends up on its own separate but parallel guideway. Both the Gerrard and Riverside-Leslieville stations and the future Ontario Line trackway are not yet visible though, for reasons much the same as for the northern elevated portion of the line.
In the shared embankment section, corridor widening work (along with corridor raising work to create higher clearances at underpasses) has progressed significantly, allowing a recent shifting of the GO tracks to lovely fresh ballast with concrete sleepers over the course of a weekend.
The retaining walls supporting the tracks in their higher and tighter-to-adjacent-development position sport unique wave patterns, and support clear sound barriers above, which should reduce the noise of this century old railway.
At the site of the massive new East Harbour station, which will eventually see service on the Ontario Line, GO’s Kitchener-Stouffville and Lakeshore East Lines as well as a new streetcar on an extension of Broadview Avenue, the new bridge over Eastern Avenue and some of the stations curved wall structure adjacent to the tracks has become visible. The Ontario Line will pass through the East Harbour site on its own guideway adjacent to the rail embankment, and will feature dead-straight platforms while the GO platforms will feature a noticeable curve.
Leaving East Harbour, the Ontario Line will cross the Don once again on an iconic arch bridge which will mirror the Humber River arch bridge to the west of Downtown Toronto. In fact the piers which will support this structure are actually already visible.
West of the Don, the Ontario line will pass between the Richmond Hill GO lines track pair and the rest of the GO tracks, and then descend into the downtown tunnel.
Downtown
Progress on the downtown section of the Ontario line is continuing rapidly, though not all of it is super visible. The eastern two underground stations on the downtown segment of the line — Corktown, and Moss Park — will both be built cut and cover, with the ground excavated and the rather large stations constructed back up, something mostly possible in this case because of the ability to secure huge sites at grade to excavate the stations.
An excellent pair of images from UrbanToronto user hawc captures the progressive excavation of the Corktown site beautifully, first top-down, then from the side.
The other four downtown Ontario Line stations will be mined, something which was done for a handful of stations on the Eglinton Line 5 Crosstown, but which has never been done at subway scale nor in Downtown Toronto. The mining approach will give the stations a distinct large tube shape, although the extent to which this is visible will be limited somewhat by the platform screen doors installed along the platform.
The mining approach will minimize site requirements on the surface and allow the various streetcar lines and roadways above the stations to be disrupted far less than would have otherwise been the case, and this means the mined downtown stations each have smaller sites where shafts will be excavated down to the future rather deep station levels before the large caverns are excavated horizontally. The construction of the shafts, which will also correspond with future entrances, has progressed to different levels at different station sites, with the tightly constrained site at Yonge and Queen just south of the Eaton Centre seemingly being the least advanced so far.
Osgoode’s shafts are rather notable because the western one, which is a block west of University Avenue, will contain one of several elevator-only entrances on the Ontario Line's downtown section. This entrance shaft will also be visually interesting because it will be connected with the main station cavern by a curved, mined pedestrian walkway that should give London Underground vibes.
Queen and Spadina perhaps best highlights the very interesting effect of constructing stations through pinhole shafts from the surface in that very little of the excavation work, or work in general going on for the eastern entrance, is visible behind the wraparound heritage facade which has been stabilized on the edge of the construction site.
West
Now, jumping southwest to beyond King-Bathurst station where there are more stabilized heritage walls for that station, the last emergency exit shaft on the downtown tunnel has visible work occurring, located right between the Kitchener and Lakeshore railway corridors at the tip of the arrowhead-shaped Liberty Village area, adjacent to the rather new Ordinance Park. This location does seem like a missed opportunity for an additional downtown station as the eastern edge of Liberty Village has a significant cluster of density that will be a rather annoying walk away from Exhibition or King-Bathurst.
Finally, work is perhaps most extensive and visible at Exhibition station, which also happens to be a very busy already existing GO station (unlike East Harbour), and which will be a major structure with a massive canopy covering both the GO and Ontario line facilities when it is completed. The existing Exhibition station had to be shifted to make way for this new facility to be built to its west, and a massive temporary overhead pedestrian bridge was added to help with passenger circulation (which is notoriously poor through the under track pedestrian tunnel) while construction progresses for the new station. The overhead bridge will be in use during the 2026 Fifa World Cup games that will be played at BMO field.
Exhibition is also the site of the first tunnel boring machine launch shaft, a structure UrbanToronto users are probably familiar with at this point (similar shafts have been built in recent years for the Scarborough Subway Extension and Eglinton Crosstown West Extension, not to mention various other projects using TBMs) which will be used to launch the machines that will excavate the downtown tunnel in the not so distant future. Interestingly, unlike most other recent Toronto subway projects, but like the Broadway Subway Extension in Vancouver and other projects internationally, the TBMs will actually pause to pass through the downtown station sites after they have already been excavated, which should compress the overall timeline needed as opposed to needing to wait for the TBM to pass the site to be able to start significant excavation as has been the case on other projects.
Now, while a lot of work on the Ontario Line is already visible, much more work should start appearing in the new year. For one, heavy construction should begin on the Don Bridges, with their towers rising from the ground and their bridge decks slowly coming into view. We should also get lots of interesting pictures of the TBMs which will be used to excavate the twin downtown tunnels before they are launched in the coming year, after which the expanded Exhibition station can begin to form. We will also likely see work progress rapidly on the operations and maintenance centre in Thorncliffe Park, which is a rather interesting facility on an oddly shaped plot of land that will be responsible for maintaining, and storing the large fleet of subway trains for the new line — deceptively many trains will be needed to hit the very high 90 second frequencies the line is designed for — as well as operating as a control centre to oversee the driverless vehicles.
Now, much has been said about the scheduling and cost blowouts on the Ontario Line (including by me at the top of the article!), but I do think when you see the extent of the project, the scale of the works and worksites, and the number of places where the Ontario Line interacts with other major infrastructure — in two cases with massive new railway stations being constructed as a result — these price and schedule problems are put in perspective. The Ontario Line is not quite everything we’ve been promised, and it will be a pricey project, but I think it's also clear that it will have an enormous lasting impact on the city's landscape, not just in the movement and development it will surely enable, but also in its heroic structures, the types of which we have not seen built here for decades, or arguably a century.
UrbanToronto will continue to follow progress on this development, but in the meantime, you can learn more about it from our Database file, linked below. If you'd like, you can join in on the conversation in the associated Project Forum thread or leave a comment in the space provided on this page.
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UrbanToronto has a research service, UTPro, that provides comprehensive data on development projects in the Greater Golden Horseshoe — from proposal through to completion. We also offer Instant Reports, downloadable snapshots based on location, and a daily subscription newsletter, New Development Insider, that tracks projects from initial application.
