One of Toronto's next key subway stations is about to cross huge milestone

It may just look like a giant hole in the ground today, but the massive pit forming at Toronto's Queen and Spadina intersection is a key step towards the construction of a critical new subway station set to serve the rapidly-densifying area.

Over the past several months, Metrolinx has been advancing work at the site of the upcoming Ontario Line's Queen-Spadina station, an underground stop on the 15.6-kilometre rapid transit line that is set to enter service in 2031 and relieve the ever-cramped Line 1 and 2 interchanges.

But before trains can zip below gridlocked city streets, crews must prepare the station sites on the line's tunnelled downtown segment for the forthcoming arrival of tunnel boring machines that are now preparing to launch from a site near Exhibition Place.

Queen-Spadina Station is technically two separate construction sites when viewed from the surface, but the two work sites will eventually form part of the same subterranean transit complex.

Excavation work for the Queen-Spadina south site is now approaching completion, and has already paved the way for the start of construction on the station's permanent components.

The underground chamber destined to become the station's platforms, where tunnel boring machines will eventually break through, currently resembles a natural cavern, a product of the sequential excavation technique being used to form the large underground void.

This phase of construction is expected to wrap up in the coming weeks, with permanent station construction to ramp up in March and continue until early 2029.

The work will involve a variety of heavy equipment, including cranes, compressors, boom lifts, concrete mixers, and other construction machinery.

As one would expect with this type of heavy gear, Metrolinx warns local residents and businesses that there will likely be noise from construction equipment as it is moved into station sites to begin the next phase of work. 

Crews will be working around the clock in shifts to move the project along, though Metrolinx notes that after-hours material movements will use the nearby north station site "whenever possible" to minimize noise disruption at the intersection.

Louder activities at the south station site will be scheduled between 7 a.m. and 11 p.m. when possible.

In addition to these scheduling considerations, Metrolinx promises that noise levels and air quality will be monitored throughout construction.

The Ontario Line is expected to wrap up construction in 2031, adding 15 new stations to the city's rapid transit network across 15.6 kilometres of new tracks.