Project Profile: Stouffville GO Corridor Expansion

The Stouffville GO Expansion is a foundational component of Metrolinx’s Regional Express Rail (RER) program, engineered to transform the corridor into a high-frequency, electrified transit spine for the Greater Toronto Area. This project delivers extensive track-doubling, new station infrastructure, and modernized signaling to enable a quadrupling of service capacity. It represents a critical upgrade to Toronto’s regional rail network, enhancing connectivity and alleviating urban congestion.

Project Fact Sheet

Technical Specifications

The core of the Stouffville GO Expansion involves significant civil and systems engineering to support dramatically increased service levels. A primary upgrade is the addition of a second mainline track across a 17-kilometre segment, effectively eliminating a key bottleneck and enabling simultaneous northbound and southbound train movements. This track-doubling is complemented by the construction of a new rail bridge over Steeles Avenue, replacing a level crossing to improve safety and traffic flow. For enhanced operational flexibility and to maintain tight headways, a new pocket track has been constructed at Unionville GO station, allowing for efficient train storage and turnarounds.

Station infrastructure has been comprehensively overhauled. The project includes the construction of four entirely new GO stations: Lawrence-Kennedy, Finch-Kennedy, Gerrard-Carlaw, and the major transit hub at East Harbour. These stations feature modern designs with island platforms, full accessibility, and integration with local transit services. Additionally, existing stations at Unionville, Milliken, and Agincourt have undergone major upgrades to accommodate increased passenger volumes. Supporting infrastructure includes the addition of 2,000 new parking spaces and the installation of advanced signaling systems compatible with the future electrified service, which is central to achieving the planned 15-minute service frequency between Union Station and Unionville.

Key Takeaways

• Quadrupled Service Capacity: The project’s primary outcome is a 400% increase in service capacity, moving from approximately 50 to 170 weekly trips and establishing a true rapid transit service level on a regional rail corridor.
• Enhanced Network Integration: With four new, strategically located stations, the line now integrates directly into dense urban neighbourhoods, providing crucial connections to the Toronto Transit Commission (TTC) network and reducing dependency on automobiles.
• Foundational RER Enablement: This expansion serves as a critical proof-of-concept and a vital link in the broader GO Regional Express Rail (RER) network, laying the physical and operational groundwork for a fully electrified, high-frequency regional system.

FAQ

When will the Stouffville GO Expansion be fully complete?
The Stouffville GO Expansion project was scheduled for completion in 2025. As of late 2025, the project is in its final commissioning and testing phase, with full, enhanced service expected to be operational shortly thereafter, marking a new era of travel along the corridor.

Who is building the Stouffville GO Expansion?
The project is being delivered by the provincial agency Metrolinx, in partnership with Infrastructure Ontario. The primary construction and project management contract was awarded to EllisDon Transit Infrastructure (EDTI), with global firm WSP providing key engineering and professional consulting services.