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Network-Wide Structures Project

Network-Wide Structures Project


As part of the GO Expansion Program, Metrolinx has identified various infrastructure required to achieve service level targets across the network.

This project represents a change that was not examined in the previously approved Barrie Rail Corridor Expansion Project Environmental Project Report (2017), and requires a Significant Addendum under the Transit Project Assessment Process (TPAP) (Ontario Regulation 231/08).

The purpose of the Project is to accommodate the expansion of the Barrie Rail Corridor through grade separating at-grade road-rail crossings. These improvements will enhance on-time performance, operational flexibility / reliability, and reduce traffic conflicts. The Project will facilitate the GO Expansion Program, including allowing for the construction of a previously approved new track. To support GO Expansion along the Barrie Rail Corridor, the following at-grade crossing will be altered:

City of Vaughan, York Region

As part of the Network-Wide Structures Project, Metrolinx has continually worked with the Town of Aurora, York Region and property owners to land on a design solution for the proposed grade separation at Wellington Street East. While progress has been made on multiple fronts, there is still work to be done to agree on a solution that meets the needs of the Town, Region, property owners and GO Expansion.

To account for the additional time needed for a design solution, Metrolinx will seek EA approval for the Wellington Street East Separation Project through a standalone addendum to the 2017 Barrie Rail Corridor Environmental Project Report (EPR). The EPR addendum will take place once work is complete to address the outstanding stakeholder concerns related to its design.

A map displaying the Barrie Rail Corridor from Wellington Street East to McNaughton Road.

Project Status

The Network Wide Structures project is currently in the Pre-TPAP Addendum Planning Phase.

Round 3 of public consultation for the GO Expansion Program was held online from November 27 to December 11, 2020. View the materials from Round 3.

Round 2 of public consultation for GO Expansion was held online from August 18 to September 1, 2020. There was no new information from the Network Wide Structures project presented in Round 2. Participants were able to read about the Network Wide Structures project and asked Metrolinx general questions about the project.

Round 1 of consultation was held in person during the month of February 2020.  To view the materials from Round 1.

The Notice of EPR Addendum is anticipated in February 2021.

A Transit Project Assessment Process (TPAP) is a focused impact assessment process created specifically for transit projects. The process involves a pre-consultation phase followed by a regulated up to 120-day phase and includes consultation, an assessment of positive and negative impacts, an assessment of measures to mitigate negative impacts and documentation.

A TPAP ensures that the natural, social, cultural, and economic environments are protected and any potential adverse effects from proposed infrastructure are either avoided, mitigated or minimized.

TPAPs are regulated by Ontario’s Environmental Assessment Act, specifically Ontario Regulation 231/08 - Transit Projects and Metrolinx Undertakings, and are submitted for the Minister of the Environment Conservation and Parks' review prior to completion.

Public, stakeholder, and Indigenous consultation occurs throughout the process.

A TPAP Addendum is carried out under Section 15 of Ontario Regulation 231/08 - Transit Projects and Metrolinx Undertakings, which includes provisions for proponents to make changes to a transit project after the TPAP Statement of Completion is submitted and approved.

If, after submitting a Statement of Completion, the proponent wishes to make a change to the transit project that is inconsistent with the environmental project report, the proponent shall prepare an addendum to the environmental project report. The following outline and figure describes the key steps in the EPR Addendum process under TPAP:

  • Prepare an assessment of the impacts the proposed change may have on the environment;

  • Prepare and distribute an Addendum report;

    Prepare and distribute a Notice of Environmental Project Report Addendum; and

  • Conduct a final review by the public and stakeholders prior to proceeding with the proposed Addendum.


All proposed new transit infrastructure as part of the GO Expansion program being assessed through the TPAP under Ontario Regulation 231/08 - Transit Projects and Metrolinx Undertakings, either as new TPAPs or as Addenda to previously completed and approved Environmental Assessments or TPAPs.