A new use for an old track: How an existing rail line provides the most environmentally-friendly location for a transit layover

Increased GO Train service will reduce carbon emissions and improve air quality by getting more cars off the road. To realize those environmental benefits, Metrolinx must build additional facilities to support additional trains. Layovers – where surplus train sets can be stored between rush hours – are an example. To minimize environmental impacts of a new layover, Metrolinx will use an old rail line that lies next to the Don Valley Parkway. Its location, under the Prince Edward Viaduct connecting Danforth Avenue to Bloor Street, takes advantage of an existing access road in an area that already saw construction when the viaduct was revitalized. Metrolinx will use landscaping to blend this facility into the surrounding green space. Pedestrians and cyclists will have continued access to the Lower Don Trail.

The work to deliver more two-way, all-day, 15-minute service on more GO Train routes includes building new facilities to accommodate trains that will be part of that expansion.

Before we can see those benefits, Metrolinx must first build new facilities across the entire network. The challenge set for the team is to build those facilities in the most environmentally responsible way possible.

That’s one reason why Metrolinx will use an existing rail line, next to the Don Valley Parkway (DVP) and under the Prince Edward Viaduct, for a layover site – a place to park unused train sets during the time between a weekday’s two rush periods. The layover will accommodate three trains at a time, parked in a straight line along the track.

Looking south, this Metrolinx rendering shows space for trains to be parked immediately west of the Don Valley Parkway, with room for buildings to be tucked into a spot north of the Prince Edward Viaduct. Artist’s rendering, subject to change. (Metrolinx image)


“With GO Expansion, in order to meet the service levels, we really do need these layover facilities across the entire GO network,” said Mirjana Osojnicki, Metrolinx Manager of Environmental Programs and Assessment.

With more frequent service throughout the day, movement of trains must be choreographed with a tight schedule.

A layover site near Union Station is required to park some of the larger unused train sets during off-peak times. This allows trains to quickly cycle on and off the corridors to bring them off after morning peak and get them quickly back to Union Station for the evening rush.

Parking unused trains during off-peak times will reduce power needs and costs. A spot is needed close to Union Station and space in the nearby Don Yard is already spoken for.

“To reduce congestion at Union, we must make sure trains quickly leave the station to allow for the continued movement of trains,” said Osojnicki.” We do need a storage facility in close proximity.”

The new layover site takes advantage of an old rail line, allowing the trains to be parked in a single line. No new track needs to be added.
While making use of an old rail line is an obvious solution, picking the exact spot was more of a challenge.

Metrolinx reviewed several places along the line before settling the exact plan.

Looking north towards Danforth Avenue, this rendering shows a line of three trains parked next to the Don Valley Parkway, under the Prince Edward Viaduct. This is an artist’s rendering and subject to change. (Metrolinx image)


“We’ve worked with the City of Toronto and the Toronto Region Conservation Authority (TRCA), through multiple iterations, to land on a design that has the least possible impact on the Don Valley,” she said. “That’s how we settled on a site location that has minimal impacts to the floodplain and buildings that are located outside of the 100-year floodplain and at higher elevation to accommodate TRCA’s regulatory storm level.”

“We have also reduced the footprint of the facility so that we are minimizing the footprint in the valley as much as possible, while meeting the minimum requirements for train storage.”

The project will include buildings for crews, waste disposal and wayside power (which means the engines will be turned off while parked at the layover), plus approximately 10 spaces for staff parking, immediately north of the viaduct. A service drive will run alongside the track.

Placing these buildings immediately north of the viaduct will take advantage of construction that has already been done in the area. This is an area where green space was previously disturbed during the rehabilitation of the viaduct and there is already an access road in place to support an adjacent hydro facility.

With the track and access road in place at this site, new ones do not have to be built, and this dramatically reduces the environmental impact.
While noise is an issue that must be managed at almost all transit sites, this spot is unique as the limited sounds will be dampened by car traffic on the DVP. The track runs under the viaduct, which carries a steady flow of car and subway traffic between Bloor Street and Danforth Avenue.
Work will be timed to minimize impacts and the public will be notified well in advance of construction.

“We will make sure the vegetation clearing will occur outside of bird breeding season and we will limit the amount of removals, as much as possible,” Osojnicki said.

While the Lower Don Trail will remain open to pedestrians and cyclists, there may be some temporary closures during construction, and they would be publicly announced in advance.

After construction is completed, the plan is to add greenery in the form of native species, contributing to the natural environment.

“It will be tucked away and we will have a landscaping plan to have it blend-in with the area,” said Osojnicki.

A combination of fences and bollards will separate the layover and buildings from public green space.

A fence around the layover facility will safely separate it from the Don Valley Trail, which will continue to be open to pedestrians. As always, this is an artist’s rendering that’s subject to change. (Metrolinx image)

This site has a smaller footprint than the original proposal. It was mapped out following the initial public consultation in February 2020 and discussions with the city and TRCA.

The environmental assessment was completed in March 2021. People living in the area and using the trails can look forward to more public dialogue in the weeks and months ahead.

“Our intent is to provide updates to community groups, so everyone is aware of the design, anticipated timeline and any temporary closures,” Osojnicki said. “Throughout the detailed design phase and construction, we will continue to engage with community groups and trail users.”


The west side of the Don Valley is not an option for the layover as the existing train tracks are currently in regular use. Also, an access road would have to be built, resulting in even more environmental impacts.

Of the new layovers that Metrolinx will need, this is one of three in the City of Toronto. The rest will be built further along the network.

Metrolinx currently has 16 layover facilities with capacity for midday and/or overnight storage of 111 12-coach trains. With GO Expansion, 42 per cent more space will be required to deliver increased service across the GTHA.

Story by Mike Winterburn, Metrolinx communications senior advisor