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Proposed Infrastructure & Studies

GO Rail Network Electrification Addendum - Proposed Infrastructure and Studies

The GO Rail Electrification Addendum will assess the additional Overhead Contact System (OCS) infrastructure required to support the proposed infrastructure as part of the GO Expansion Program, which includes new and updated tracks and train layover/storage yard facilities. The Addendum will also assess the potential impacts and mitigation for system-wide operational noise, vibration, and air quality for future service levels identified in the GO Expansion Business Case.

Electrification for Proposed Infrastructure in the GO Expansion Program

The 2017 GO Rail Network Electrification Transit Project Assessment Process (TPAP) identified infrastructure required to convert Metrolinx-owned rail corridors from diesel to electric propulsion. Since then, additional electrification infrastructure requirements for new/upgraded tracks and layover facilities have been identified at various locations across the network to achieve increased service levels in the GO Expansion Business Case. The new infrastructure that will require electrification are presented in: New Track and Facilities TPAP and Scarborough Junction Grade Separations.

Electrification infrastructure requirements for new/upgraded tracks and layover facilities will include additional Overhead Contact System (OCS) infrastructure which is described below.

Overhead Contact System (OCS)

  • OCS is the aerial supply system and associated equipment and hardware that deliver the 2x25 kV ac traction power from Traction Power Facilities to the pantographs of electric trains. The    OCS comprises the catenary system (messenger and contact wires, stitch wires and hangers), autotransformer feeder conductors, associated supports and structures (including poles, portal structures, head spans, etc.),  
  • OCS is supported by cantilevers and portal structures. 
  • Maximum distance between OCS supports is approximately 65 m.

Black and white image showing the overhead contact system is supported by the cantilevers and connects to Metrolinx traction power facilities and to the Hydro one component.


Cantilevers: one foundation required


Portals: foundations to be installed on either side of tracks

For more information about the proposed Walkers Line Layover (Lakeshore West corridor), Unionville Storage Yards (Stouffville corridor), and new tracks and switches, visit New Tracks & Facilities. View information on the electrification of the Midland Layover (Lakeshore East corridor) as proposed under the Scarborough Junction Grade Separation.

Benefits of Electrification

  • A faster, more attractive service, including trains that accelerate faster and stay at top speed for longer, saving customers time.
  • A more efficient, reliable service with more frequent trips and lower operating costs.
  • Reductions in greenhouse gas emissions and improved local air quality.

Train Operations on Partially-Electrified Corridors

  • Once electrification is implemented, Metrolinx will maintain a mixed fleet of both diesel and electric trains. Partially-electrified corridors will continue to support diesel train service for areas beyond the electrified portions of the corridor.
  • Passengers will not be required to switch trains to travel past the point of electrification.

Hydro One Conflict Areas - UPDATED INFORMATION

As part of the Electrification Program, Metrolinx is working with Hydro One (as Co-Proponents) to define the areas in the vicinity of Metrolinx rail corridors where proposed electrification infrastructure will conflict with existing Hydro One transmission lines and to establish environmental assessment requirements that need to be fulfilled for the identified conflict areas, that were not previously assessed as part of the 2017 GO Rail Network Electrification EPR. Specifically, Hydro One Conflict Areas have been identified within the Union Station Rail Corridor (USRC) and surrounding areas. View details regarding the identified conflicts, proposed solutions, and cultural heritage studies undertaken as part of the Significant Addendum were presented during Round 2 of public consultation.

From February 2 to 11, 2021 we sought public feedback on an update regarding the proposed scope of work at the existing and new Don Fleet Junction. Proposed works at the Don Fleet Junction (JCT) are required to support the resolution of Hydro One conflicts within the Union Station Rail Corridor (USRC) previously presented. Upgrades to the existing Don Fleet JCT (east side of Lower Don Trail) and construction of the new Don Fleet JCT (west side of Lower Don Trail) are required for the transition of the underground transmission circuits to overhead circuits. Read details regarding the proposed Don Fleet Junction scope of work.

Studies, Impacts, and Mitigation

Environmental studies are important components of a TPAP Addendum. Along with public feedback, they inform the Environmental Project Report (EPR) Addendum that becomes subject for public review and the Minister’s approval.

These studies look at existing conditions to assess potential impacts from construction and operation of the proposed infrastructure and future train service, recommend mitigation/monitoring commitments, and provide key information for concept designs. Please visit the EPR Addendum page for more information. Please note that a number of technical reports/studies prepared as part of the New Track & Facilities TPAP and Scarborough Junction Grade Separations TPAP are referenced and where applicable are included as an appendix to this EPR Addendum.  

View the impacts and mitigation measures associated with the Midland Layover. 

View additional information about System-Wide Operational Noise, Vibration, and Air Quality impact assessments and proposed mitigation.

Vegetation Guidelines

Vegetation removal is a GO Expansion program safety requirement. It ensures safe delivery and operation of the new infrastructure required to support electrification and service increases. A vegetation control zone, identified as part of the GO Rail Network Electrification 2017 Transit Project Assessment Process (TPAP), will be established to: 
•    Protect infrastructure, including that for electrification; 
•    Increase operational reliability and minimize safety concerns associated with the risk of tree limbs falling onto overhead wires; and 
•    Accommodate for worker and operational safety through the preservation of sightlines. 
Additional tree removals may also be required when constructing new tracks, new layover facilities, and other infrastructure.

To accommodate GO Expansion, Metrolinx has developed a tree compensation and vegetation management strategy that will leave the region a much greener place in the process.  Metrolinx is working closely with local regional conservation authorities – Toronto and Region Conservation Authority (TRCA), Lake Simcoe Region Conservation Authority, Conservation Halton, Credit Valley Conservation, municipal partners, and other organizations on these efforts to increase the vegetation cover in the region. 

To learn more about Metrolinx’s Vegetation Management  and Tree Compensation Program , please visit:  metrolinx.com/vegetation   

Key Preliminary Design and Construction Commitments

Read about Metrolinx’s key preliminary design and construction commitments related to proposed new infrastructure.