> Yonge North Subway Extension - Environmental Project Report Overview | Metrolinx Engage

Yonge North Subway Extension - Environmental Project Report Overview

Providing reliable, safe and accessible public transportation brings environmental and social benefits. Metrolinx is committed to protecting the environment, while working to provide an integrated and sustainable transportation system.

To maintain strong environmental oversight, Metrolinx is conducting an addendum to the previously-completed environmental project report (EPR) – which includes studying existing environmental conditions and completing an environmental impact assessment.

The results of these studies will be presented as part of future public meetings and will be available for public review within the EPR Addendum.

The study area for the project extends north from the existing Finch Station in Toronto to just north of 16th Avenue in Richmond Hill.

Metrolinx is carrying out an addendum to the previously completed EPR in accordance with Ontario Regulation 231/08: Transit Projects and Metrolinx Undertakings (O. Reg. 231/08) made under the Environmental Assessment Act.

The regulation outlines an EPR addendum process that includes:

  • Public, regulatory agency and Indigenous community notification and consultation for significant changes to the project.
  • Documentation requirements for addenda to an Environmental Project Report, including description of and reasons for changes, and evaluation of impacts that changes might have on the environment.

Public consultation will continue through throughout the Environmental Project Report Addendum process.

As part of the EPR Addendum process, we aim to begin consulting on specific items, including:

  • Results of our existing environmental conditions studies
  • Results of our environmental impact assessment studies, such as noise and vibration, and the solutions proposed to reduce those impacts

Your input matters. Share your ideas and feedback with us to be included in the Environmental Project Report Addendum, which will be a permanent public record. Submit your comments via email, through our Ask a Question forum, or at one of our live virtual events.

The updated environmental studies are building off the work previously done on the Yonge North Subway Extension, including:

2009 – Environmental Project Report (EPR)

  • Proposed 6 stations
  • Proposed bus terminals at Steeles Station and Richmond Hill Centre Station

2014 – EPR Addendum

  • Included a train storage facility north of Richmond Hill Centre Station
  • Extended the project one kilometre north

2021 – Initial Business Case

  • Establishes why the project should be pursued
  • Provides evidence on viability of options
  • Brings forward new route proposal for consultation

2021/2022 – EPR Addendum

  • Assesses proposed changes to the project, including changes to route, stations and train storage facility

The EPR Addendum for the Yonge North Subway Extension will study and assess the proposed changes to the project outlined in the Initial Business Case, including:


  • Extends service roughly 8 km north from Finch Station in Toronto to north of High Tech Road in Richmond Hill
    • ~6 km underground
    • 2 km at surface level
      • An additional 1 km of surface-level track will be built at the north end of the extension to support subway operations
  • Studying the new location of Bridge Station (formerly Langstaff Station)


  • Tunnels will be excavated using two tunnel boring machines
  • Studying one launch shaft and one extraction shaft for tunnel boring machines
    • Previous environmental studies assessed multiple launch and extraction shafts

Track Work

  • Two tunnels between Finch Station and the portal, which is the point at which trains enter and exit the tunnels
  • One track within each tunnel
  • Two tracks along surface-level portions will run from the portal to the train storage facility

Train Storage Facility

  • At-grade facility that accommodates up to 15 six-car trains
  • Where trains will be stored, inspected, lightly cleaned, and dispatched

Traction Power Substations

  • Houses electrical and mechanical equipment that support the subway system
  • Will be located along the route as needed

Emergency Exit Buildings

  • These small, one-room buildings allow people to quickly and safely reach the surface level in case of emergency
  • Buildings will be used to access the tunnels for maintenance
  • The locations of emergency exit buildings are based on safety guidelines

We are taking a close look at existing environmental conditions to make sure we have a comprehensive understanding of how all the things that exist today within the project area could be affected by – or could affect – the new transit Metrolinx is building for tomorrow. We are also working to identify the right mitigation solutions. The environmental factors we are studying include:

Natural Environment

  • Plant inventories
  • Fish habitat assessments
  • Bird surveys
  • Wildlife habitat assessments
  • Species at risk surveys

Cultural Heritage

  • Research and document historical homes and properties
  • Surveys of buildings, areas and features (landmarks) with potential heritage significance

Air Quality

  • Review data from air quality monitoring stations
  • Identify places sensitive to air quality issues, like:
    • Schools
    • Hospitals
    • Care facilities
  • Predict air quality based on potential changes the project will bring

Noise and Vibration

  • Measure and document current levels of noise and vibration
  • Identify places sensitive to noise and vibration, like:
    • Residences
    • Schools
    • Hospitals
    • Care facilities
  • Investigate potential solutions


  • Review of potential impacts to traffic during construction and operations:
    • Automobile traffic and transit services
    • Pedestrians and cyclists

Land Use and Socio-Economic Impacts

  • Review of how surrounding land is used, and plans for future development
  • Identify socio-economic and land use features, like:
    • Bicycle and pedestrian routes and multi-use trails
    • Parks and open spaces
    • Places of worship


  • Review records and perform on-site research to determine areas with potential for archaeological finds
  • Confirm whether there are any known archaeological sites
  • Engagement with Indigenous Nations