Serving as Downtown Toronto’s busiest intermodal transit hub, Union Station is traversed by roughly a quarter million commuters on any given weekday. The ongoing revitalization of the 86-year old Union train Station—and National Historic Site—has seen much coverage on UrbanToronto, due in part to the high visibility of exterior elements, like the new glass train shed, the restored copper roof and stone work, and in part due to the City-organized tours of the work taking place under the tracks.

There is a whole lot more going on below Front Street too.

Union subway Station is very busy. Over 100,000 daily subway commuters make use of this southernmost subway station on the TTC’s Yonge-University-Spadina line. Anyone using it during the increasingly long rush hour experiences the crush of people passing through. In recent years, developers have been building out much of the once sparsely inhabited land south of Union Station, and the resulting influx of new residents and workers has pushed Union’s narrow, stair-filled centre subway platform well past capacity.

Morning rush at Union Station, image by Jack Landau

At 59-years old, Union is one of the original twelve subway stations opened by the TTC in 1954. In the years that the line was under construction, Toronto’s population was hovering above 675,000 residents, and daily ridership figures were projected at a fraction of that number. The original planners, engineers and designers of the initial line between Union and Eglinton could not possibly have foreseen the explosive growth the city would experience in the following decades, leaving the task of modernizing an aging system to the thinkers of today.

The solution? Construction of a brand new subway platform on south side of the existing subway tracks, which will separate the two passenger flows, with the existing 6.9 metre-wide platform serving University-Spadina-bound trains, and the new 10 metre-wide south platform serving busier Yonge-bound trains.

Rendering of Union Station's under-construction second platform

Diagram of both existing and new platform configurations

Construction work on the second platform and its associated infrastructure has been moving west to east, starting with the excavation for the west fire vents. The now-structurally complete western fire vent shaft sits several meters below Front Street, level with the subway tracks to the immediate north.

Temporary stairs leading down the western fire shaft, image by Jack Landau

These vents can be opened or closed to either allow or block air from moving into the subway tunnels. In the photo below, the temporary corrugated metal hoarding lining the cutout which will soon hold large ventilation fans is all that separates the construction site from the active subway Union subway platform. The western vent is nearly complete and currently being backfilled.

Western fire vent, the existing Union subway platform sits just beyond the metal hoarding, image by Jack Landau

To the immediate east, the largely completed western concourse is now serving as a temporary entrance/exit for Union subway station. The wide concrete stairs leading to this entrance, visible in the photo below, will be repeated twice more in the centre and eastern concourses, which are currently being excavated to the immediate east. This widened arrangement of stairs and entrances will help to ease the congestion frequently seen at this hub during busy rush hour traffic.

Temporary concourse at Union Station, image by Jack Landau

The new stairs above are temporary. Once the new GO York Concourse is complete—a new west side access to GO Trains—the Go Bay Concourse will close for rebuilding. The new Bay Concourse will be at the same level as the subway exit, alleviating the need for stairs here. Expect several more changes to this area as the work progresses in stages over the next few years.

In the past several months of work on the station’s reconfiguration, many commuters have become familiar with the temporary collector stations on concourse level, though few give much thought as to what might be found behind an inconspicuous grey door directly behind one collector station.

Temporary fare collector station at Union Station, image by Jack Landau

Behind that door, a temporary staircase leads down to platform level, where telltale features of a roughed in subway platform become immediately apparent.

Platform level in the under construction second platform, image by Jack Landau

As was the case with the western fire vent, the second platform’s construction area is separated from the busy subway tracks just beyond by a layer topped in corrugated metal construction hoarding. The edge of the new platform will extend a few inches beyond the construction hoarding, while everything on the side visible in the photo below will be platform space for commuters to wait for Yonge-bound trains.

The future edge of the second platform lies just a few inches beyond the corrugated metal hoarding, image by Jack Landau

To the east, excavation is nearly complete for the centre and western sections of the platform and their respective concourses, as well as the eastern fire vent shaft.

Excavation for Union subway station's second platform, image by Jack Landau

The 35-foot deep open-cut trench below Front Street is being excavated in a very tight location, with concrete box of the existing subway tunnel to the north and various other obstacles all around. The diagonal bracing seen in the excavation pit serves to keep the subway tunnel supported as generations of undisturbed soil are removed around it.

Inside the excavation pit for Union subway station's second platform, image by Jack Landau

Though the project has taken great care in preserving the subway tunnel which the new platform will serve, other tunnels had to be sacrificed in order for this infrastructure project to happen, including a pedestrian PATH passageway, and more notably, a TTC passageway to the Harbourfront LRT platform.

A TTC tunnel and a pedestrian tunnel were sacrificed for the excavation, image by Jack Landau

Here is a closer look at the bisected Harbourfront LRT passageway, still sporting its original tiles.

Looking into the former TTC Queens Quay streetcar tunnel, image by Jack Landau

On the eastern edge of the construction site, prep work is underway on the eastern fire vent, as well as a new automatic entrance to the Brookfield Place PATH tunnel.

Underneath Front Street at Bay where the eastern fire shaft is being constructed, image by Jack Landau

A new entrance to the Brookfield Place PATH tunnel is in the works just behind this blue tarp, image by Jack Landau

While TTC commuters at Union Station will have to continue enduring their daily dose of claustrophobia for several more months, the opening of the partially complete platform, slated for next summer, will greatly reduce congestion even as work continues on its finishing touches. After the second platform opens to the public, the existing platform serving the less crowded University-Spadina line will be closed in small sections, at which point the station’s aging tile and dusty finishes will be fully restored.

Rendering of Union Station's under-construction second platform

Looking for more information about the Union Subway Station second platform? Project facts and renderings can be found in our dataBase files, linked below. Want to get involved in the discussion? Join in the conversation in our associated Forum threads, or alternatively, voice your opinion in the comments section provided at the bottom of this page.