This Backgrounder provides highlights of the staff report “Next Steps on the Scarborough Subway Extension“, which is being considered by Executive Committee at its meeting of March 7, 2017. A Fact Sheet, which provides information with respect to the Scarborough Subway Extension ridership numbers discussed in the staff report, is also available.


  • The City of Toronto, together with the Toronto Transit Commission (TTC), is planning an extension to the Bloor-Danforth Subway (Line 2) to better serve residents. The Scarborough Subway Extension (SSE) will replace the aging Scarborough RT and contribute to an integrated and comprehensive rapid transit network that will improve transit service in Scarborough and across Toronto.
  • The SSE project was first approved by City Council in late 2013 and has advanced through the initial concept development and early planning phase.
  • The SSE is one element of the Scarborough Transit Network Plan. Work is also underway on preliminary design of the Eglinton East LRT, and SmartTrack station planning in Scarborough.
  • In July 2016, Council adopted EX16.1, Developing Toronto’s Transit Network Plan to 2031, which included direction to remove the three-stop SSE from consideration, and to develop an express option as part of an optimized transit network for Scarborough that also includes an Eglinton East LRT. Council also directed staff to retain services to undertake a third-party review of costs and risks to date.
  • In response to City Council direction, TTC and City staff have undertaken further assessment on the preferred alignment for the SSE. An update to the initial business case assessment concludes that the McCowan alignment best meets transit operations needs and encourages the development of the Scarborough Centre into a vibrant urban node as envisioned by Toronto’s Official Plan.


About the report

  • The staff report to Executive Committee:
    • provides an update on planning work for the SSE;
    • recommends an alignment along the McCowan corridor and a preferred bus terminal configuration (the Triton Bus Terminal concept);
    • summarizes the results of a third-party review of costs and risk assessment for the project;
    • outlines an analysis of procurement options for the SSE and recommends a procurement approach;
    • seeks approval to initiate the Transit Project Assessment Process (TPAP), including submission of an Environmental Project Report (EPR) to Ontario’s Minister of the Environment and Climate Change; and
    • recommends that Council request the Province and the Federal Government to confirm sources of funding for the commitments to the SSE project.


SSE Project Cost/Budget/Funding

  • The estimated construction cost for the McCowan express option with an at-grade bus terminal option is approximately $3.159 billion. This is the option that was presented in the July 2016 initial business case for the SSE.
  • Following work by the City and the TTC, the report recommends an optimal Triton Bus Terminal design to achieve the project objectives of supporting growth at Scarborough Centre, which costs $187 million more than the at-grade bus terminal.
  • The report indicates a construction cost estimate for the SSE project of $3.346 billion, based on the recommended McCowan alignment and the recommended Triton Bus Terminal design. This estimate was based on less than five per cent design and is considered to be a Class 4 estimate as per the Association for the Advancement of Cost Engineering scale, with an accuracy of minus 30 per cent to plus 50 per cent.
  • As design of the project continues, the cost estimate for the SSE project will be further refined based on the higher level of design and project scope definition and will be considered to have a higher level of accuracy.
  • Design of the SSE is about five per cent complete. The City and TTC will continue to refine the concept to ensure that the design supports growth and development in the area, while minimizing cost and impact to private properties. As design of the project continues, the cost estimate for the SSE project will be further refined based on the higher level of design and project scope definition and will be considered to have a higher level of accuracy.
  • As per the recommendation of the report, when the design reaches 30 per cent completion, staff will prepare and present a full budget estimate and schedule to the TTC Board and City Council for approval, prior to proceeding with procurement.
  • At the request of Council, a third-party expert reviewed the cost estimate for the McCowan alignment with the at-grade bus terminal, and concluded that the cost estimate for the project is valid and appropriate for the current level of design (two to five per cent complete).
  • In addition, a value engineering (VE) team reviewed the current design for the McCowan alignment with the at-grade bus terminal, to investigate opportunities to reduce construction costs, optimize construction, or reduce maintenance. The VE team reviewed the project’s risk assessment, schedule and cost estimate, made recommendations in these areas, and generated a number of ideas that will be considered through the design process. The VE team also found that work to date regarding the project’s risk assessment is in keeping with industry practice and is developed beyond typical expectations at this early stage in the project.
  • The SSE project has received funding commitments from both the federal and provincial governments and the City and the TTC will work towards reaching formal funding agreements.


Procurement method

  • The report recommends that Council authorize the City and the TTC to procure the SSE through a “Design-Build-Finance” procurement model, subject to certain conditions being met. If the conditions are not met, then the City and TTC would be authorized to procure the SSE through a single-contract Design-Bid-Build model.
  • The objective of the Design-Build-Finance approach is to transfer design-related risks (such as additional costs resulting from design errors and omissions, unforeseen site conditions etc.) to the private partner and also to provide the private partner with the latitude to consider innovative design and construction approaches.
  • The benefit of the Design-Build-Finance model is that it would enhance accountability to schedule and budget through efficient and competitive design decisions where the contractor has discretion. This approach has the potential to most effectively allocate project risks (particularly design risk).


The McCowan alignment

  • City Council received an Initial Business Case (IBC) for the SSE at its July 2016 meeting. The IBC examined options from a four case perspective: strategic, economic, financial and deliverability. The preferred option according to the IBC was the extension of Line 2 along the McCowan corridor – express from Kennedy Station to Scarborough Centre.
  • Council directed staff to consider other possible subway alignment options. After staff consideration of other express options, an update to the IBC concludes that the express subway extension along McCowan is preferred, as it best supports the development of Scarborough Centre into a vibrant urban node.
  • A significant advantage of the preferred McCowan alignment is that it doesn’t require that the Scarborough RT be closed during construction of the subway. The McCowan alignment:
    • better serves existing destinations, population and employment;
    • is close to the McCowan Precinct, where future growth is planned; and
    • supports plans to orient development around the McCowan Road corridor and Scarborough Centre Gateway at McCowan Road and Bushby Drive/Town Centre Court.


The Triton Bus Terminal

  • A key component of the SSE alignment is the station design, including all elements needed for the station to operate as a transit hub. A significant station element is the bus terminal, as it provides key transfer for many local and regional routes.
  • The future Scarborough Centre station will require a new bus terminal to accommodate an expansion of bus networks including TTC and GO Transit, as well as Durham Rapid Transit and private inter-city carriers.
  • The cost estimate for the SSE project presented to Council in July 2016 was based on an at-grade bus terminal concept, which would span about 400 metres from Triton Road to Corporate Drive, between McCowan Road and Borough Drive.
  • In the report, staff do not recommend the at-grade terminal concept because it would have a negative impact on development potential and create a barrier between the subway station and the McCowan Precinct, where future growth is planned.
  • The report recommends that the stacked Triton Bus Terminal concept be pursued rather than the at-grade design to achieve important planning and urban design goals. The Triton Road Bus Terminal will enable an urban street grid and better pedestrian connections in the area and unlock the greatest amount of development potential around the subway station.


Property Requirements

Based on the McCowan alignment, 42 affected properties have been identified: full property interest in one commercial property (for a traction power substation) and partial property interest in 35 private properties and six properties under City of Toronto, provincial or federal ownership. One-on-one meetings with affected property owners will take place during the first week of March.


Next Steps

  • After City Council has adopted a preferred SSE alignment, the SSE project team will complete the Environmental Project Report, which will be followed by a public review period and a period of review by the Minister of the Environment and Climate Change. Once the Minister gives notice to proceed with the project, the TTC and City will file a Statement of Completion and will proceed with project procurement and construction.
  • In late 2018, City and TTC staff will report on:
    • The Class 3 cost estimate (approximately 30 per cent design completion), which is suitable for establishing the project’s budget and schedule baseline;
    • An updated budget to reflect best practices recommended by KPMG; and
    • An updated funding and financing strategy, including the status of intergovernmental funding agreements with the provincial and federal governments.
  • Construction of the SSE is expected to take approximately six years, with the subway starting service in 2026.


Media contact: Wynna Brown, Strategic Communications, 416 392-8937,