One of the largest transit projects in Canada, the Ontario Line will be a 15.6-kilometre subway line in Toronto running from Exhibition Place, through the heart of downtown, all the way to Line 5 Eglinton at Don Valley Station. With 15 stations, including six interchange stations, the new line will provide more than 40 connections to bus, streetcar, light-rail transit and regional rail services.
AECOM is proud to work Metrolinx in designing and delivering the Ontario Line, a 15.6-kilometre subway line in Toronto that will connect communities and people to opportunities. This transformative project will improve commute times, reduce crowding on existing transit routes, expand access to jobs, ease traffic congestion and reduce greenhouse gas emissions. Thousands of jobs are expected to be created during design and construction.
With more than 40 connections to other transit options, the Ontario Line will knit together regional transit, putting over 227,500 more people within walking distance of transit.
AECOM, as part of both Ontario Transit Group for the Southern Civil, Stations and Tunnel contract and Pape North Connect for the Pape Tunnel and Underground Stations contract, is providing technical design leadership for the entire approximately nine-kilometre twin-tunnel system and four stations of the 15 stations, Queen, Osgoode, Cosburn, and Pape, including three technically complex interchange stations, helping connect communities and drive economic growth across the Greater Toronto Area (GTA).
Across these scopes, AECOM helps connect complex station, tunnel, civil and systems requirements into an integrated transit infrastructure that supports operational readiness, reliable performance and a safer, more intuitive experience for customers and communities.
Tunnels
The Ontario Line tunnelling work is a key component of the underground infrastructure, delivering twin bored tunnels through downtown Toronto and the eastern corridor. Excavation is being carried out using tunnel boring machines (TBMs) launched from major shafts at Exhibition Place and Gerrard–Carlaw, which serve as deep construction and logistics hubs for segment assembly, spoil removal, and TBM operations. The tunnels pass beneath existing Toronto Transit Commission (TTC) infrastructure, utilities, waterways, and dense urban development, with continuous settlement monitoring and risk controls integrated into both design and construction.
The tunnel system consists of twin circular bores that form a standalone, dual-track rapid transit corridor. Each tunnel contains track infrastructure and integrated systems for power, signalling, ventilation, drainage, and communications, supporting fully automated operations. The tunnel alignment connects to station caverns and transition structures, including at the Don Yard interface, where the line emerges to connect to the above ground sections of the Ontario Line. This project is effectively carving out the first new subway tunnels in downtown Toronto in over 60 years, enabling a major expansion of underground transit capacity while minimizing surface disruption through mechanized excavation and precast segmental lining.
Queen Station
The Ontario Line Queen Station is a deep underground interchange beneath Queen Street West and Yonge Street in downtown Toronto, providing a direct connection to the existing TTC Line 1 Queen Station. The station will be constructed at approximately 40 metres below grade in a highly constrained urban environment, requiring complex excavation and underpinning beneath active streets, utilities, and adjacent buildings. The station design integrates with existing TTC infrastructure and introduces new underground platforms, concourses, and vertical circulation to support high passenger volumes and efficient transfers.
At the surface level, Queen Station will use existing TTC entrances, with additional infrastructure to improve accessibility and passenger flow. The station is designed for clear wayfinding and intuitive pedestrian flow between street, concourse, and platform levels, enabling straightforward navigation through one of the network’s busiest nodes. Once complete, it will significantly enhance interchange capacity between the Ontario Line and Line 1 and improve access to the surrounding downtown retail and employment district.
Osgoode Station
The Ontario Line Osgoode Station is a deep underground interchange beneath Queen Street West and University Avenue in downtown Toronto, providing a direct connection to the existing TTC Line 1 Osgoode Station. At approximately 40 metres below grade, it is one of the deeper stations on the alignment and is embedded within a highly sensitive institutional and heritage context, adjacent to Osgoode Hall and key civic landmarks. The design integrates with the existing TTC station and introduces new underground platforms, concourses, and vertical circulation elements to support efficient transfers at a high-demand downtown transit node.
Surface access will be provided through two new entrances: a primary entrance at the northwest corner, extending into the Osgoode Hall grounds, and a secondary entrance at Queen Street West and Simcoe Street, which incorporates the historic CIBC building. The design carefully preserves and protects surrounding heritage features, including Osgoode Hall, University Avenue monuments, and the CIBC heritage building, through detailed coordination and staged construction planning.
Cosburn Station
The Ontario Line Cosburn Station is an underground station at Pape Avenue and Cosburn Avenue in Toronto’s East York area serving the surrounding Pape Village and residential East York communities. The design includes an underground station box built using cut-and-cover methods, with street-level entrances, ventilation structures, emergency egress, and required utility relocations.
Cosburn Station will provide local rapid transit access and connect the area to the broader Ontario Line. It is expected to improve transit access for nearby residents, generate strong local ridership, and reduce reliance on surface transit and on nearby Line 2 access points.
Pape Station
The Ontario Line Pape Station is a major underground interchange at Pape Avenue and Danforth Avenue in Toronto, linking the existing TTC Line 2 Bloor–Danforth station with a new perpendicular Ontario Line station built beneath and adjacent to the TTC’s existing infrastructure. Pape Station is a major node in Toronto’s transit network, a prominence that will be further enhanced by the Ontario Line.
Built in a dense urban setting within Greektown, the station requires complex staging, deep excavation, and underpinning in proximity to live subway operations. The design includes underground platforms, caverns, vertical circulation, and multiple entrances to improve pedestrian access and distribute passenger flows throughout the surrounding neighbourhood.
As a key interchange hub, Pape Station will improve network resilience and provide an alternative east–west downtown connection. It will help relieve congestion at Bloor–Yonge Station and improve overall Line 2 load distribution. The station will enhance local access to Greektown and Danforth Avenue and support high transfer volumes as a major node within the Ontario Line system.
