Massive Ontario transit project is taking shape over a major highway

Construction on the Hazel McCallion LRT's elevated guideway is officially nearing completion, and Metrolinx is giving commuters a closer look at how the new rail bridge is being built over one of the province's busiest highways.

The elevated section of the 18-kilometre light rail transit (LRT) line is set to carry trains over Highway 403 in Mississauga, which will connect the future City Centre stop at Rathburn Road to the Robert Speck stop on Hurontario Street.

Metrolinx recently shared a video detailing how crews constructed the complex structure, from laying its foundations to installing the massive girders that support the future rail line.

How do you build a rail bridge over an active highway while keeping traffic moving below? Have a watch to find out!

The Hazel McCallion Line's elevated guideway over Highway 403 is nearing completion after years of careful planning, engineering, and construction. This landmark… pic.twitter.com/xf8v0XrzKH

— Metrolinx (@Metrolinx) August 13, 2026

As the video notes, before construction could begin, crews had to carefully plan traffic management, crane locations, and safe work zones around the busy highway. The next step was building the guideway's foundation, which involved installing piles and pile caps, followed by pier columns and pier caps to help distribute the bridge's weight evenly.

Using specialized equipment, crews installed 69 massive girders ranging from 13 to 40 metres long. The horizontal beams essentially form the backbone of the bridge and will eventually support the heavy trains that will travel across it.

The final girders were installed over Highway 403 in fall 2024, after crews wrapped up the previous installation over the highway's eastbound lanes that summer.

Once the girders were in place, crews constructed the bridge deck and safety edge barriers. Over the next while, Metrolinx says work will focus on installing the track, railings, communications systems, and signal infrastructure.

Construction on the elevated guideway began back in 2021 and is now nearing completion, marking the final chapter of one of the more complex parts of the Hazel McCallion project.

Once complete, the line is set to run 18 kilometres between Port Credit and Brampton Gateway Terminal at Steeles Avenue, with 19 stops along Hurontario Street. The forthcoming line, named after former longtime Mississauga mayor Hazel McCallion, will connect commuters to major transit networks, including GO Transit, MiWay, and Brampton Transit, as well as the Mississauga Transitway and Züm.