Adelaide Street will be under heavy construction until the spring of next year as preparations begin on the Ontario Line subway extension that will run along Queen Street.

The City of Toronto announced Thursday that the construction will begin this week and take place on Adelaide in sections spanning from Bathurst Street to Parliament Street “to upgrade critical water, road and cycling infrastructure, as well as to reinstate TTC streetcar tracks in advance of Ontario Line construction.”

“The project, in coordination with the TTC and Metrolinx, bundles several construction needs on Adelaide Street into one project to complete the work as quickly as possible and minimize prolonged disruption,” the city announced in a press release.

The reinstating of a streetcar route on Adelaide comes in advance of the expected years-long closure of a stretch of Queen Street to both cars and public transit while the new Ontario Line subway extension is built.

The 15.6-kilometre, 15-stop extension will run from Exhibition Place through the downtown core along Queen Street, eventually coming above ground to join an existing GO train track near the Don River before heading north along Pape Avenue to the Ontario Science Centre.

The city says the work along Adelaide will include:

• Renewing the roadway on Adelaide Street from Spadina Avenue to York Street

• Reinstating streetcar tracks on Adelaide Street from Charlotte Street to York Street

• Relocating the cycle track on Adelaide Street, from Bathurst Street to Parliament Street, to the north side of the street

• Upgrading pedestrian infrastructure at various locations along Adelaide Street from Spadina Avenue to York Street

As of Oct. 24, there will be numerous closures along Adelaide, including many areas where traffic will be reduced to one lane and where cyclists will have to share the roadway with motorists.

“Construction is anticipated to be completed in spring 2023. Depending on progress, lanes may re-open during winter months and close again for finishing touches when weather warms,” the city said.

The city is urging drivers to avoid the area unless their destination is on Adelaide but says that pedestrian access to businesses along the street will be maintained.

“With so much construction taking place in the downtown core, drivers are advised to plan their travel in advance, expect delays, consider taking public transit and obey signage around work zones for the safety of the work crews.”