Port Credit GO Station will be an important hub for passengers connecting between the new Hazel McCallion LRT (previously known as Hurontario LRT) and the existing Lakeshore West Line. By installing what’s known as a ‘push box’, it will create a space for the LRT line under the GO Train tracks – while keeping the GO Trains running above – is an exciting engineering challenge. The solution is a new technique known as the Verona System, and Metrolinx News explains how it works.
Keeping Lakeshore West GO Trains running smoothly through the station at Port Credit, while tracks for the Hazel McCallion Light Rail Transit (LRT) line are laid underneath, is a priority for Metrolinx.
Its contractor, Mobilinx, will do this using an innovative engineering technique called the Verona System.
Mobilinx will use three temporary bridges, below the existing tracks, before laying new underground LRT tracks, and installing the permanent foundations for the street level GO tracks.
In the first step, the push box was built.
This is a large concrete structure that will serve as the underpass for light rail vehicles travelling under the Lakeshore West Line. It includes a partition wall separating north and southbound vehicles.
The box was built in an open area, benefiting customers, by keeping this part of construction away from the GO line. Placing it under the existing tracks, while minimizing disruption is the goal.
Next, four rows of micropiles (very strong pieces of metal used for a foundation) along with pile caps will be installed along the existing GO tracks at the station. Once completed, 11 beams in trenches, under those tracks, will span the four rows of micropiles. After the beams are in place, three temporary modular bridges – one for each current street-level track – must be created to hold up those tracks up during the next stage.
To get the box in place, crews will use an approach called “box-jacking”: pushing it underneath the GO tracks, while excavation work clears a path for it.
The three temporary bridges will support the street-level GO tracks, while the box is being jacked. Afterwards, those bridges will be removed, and the train loads will be safely transferred to the top of the push box.
The Verona System minimize impact on train schedules, work time at the station, noise and pollution. It also improves overall productivity of construction and quality of the infrastructure. The majority of this work in Port Credit will be done at night, to further reduce the impact on customers’ travel.
“This is the first time a Verona System is being deployed in Canada,” said Mobilinx assistant project manager Gavin Lobo.
“This innovative technique designed by Petrucco will ensure minimal disruption to train service while the push box is installed.”
You can stay updated on Hazel McCallion LRT line progress by following the project on Twitter.
Story by Erika D’Urbano, Metrolinx senior advisor, rapid transit