Originally, SmartTrack was to be a new rapid transit service with 22 stations (of which 14 would be new) along the inner portions of the Kitchener, Lakeshore East and Stouffville GO commuter train corridors.
As of 2021, SmartTrack is a proposal to construct five new GO stations along the existing Kitchener, Lakeshore East, Stouffville and Barrie services.
The SmartTrack line as originally proposed would be 53 kilometres (33 mi) long and run along Eglinton Avenue from Matheson/Airport Corporate Centre in Mississauga to Mount Dennis before turning downtown to Union Station.
[8] SmartTrack would complement the Government of Ontario's plan to electrify the entire GO Transit network over the next 10 years to provide regional express rail (RER) to the Greater Toronto and Hamilton Area.
Residents of Etobicoke and Scarborough would take an express bus to their closest SmartTrack station instead of the distant terminuses of Line 1 and 2.
By diverting these passengers SmartTrack would also benefit North York commuters on the current overcapacity feeder bus routes to the Line 1 subway.
[12] A city staff report presented to Toronto's executive council in March 2016 says that in order to accommodate a “separate and parallel” SmartTrack service, as Tory had promised, would require two additional tracks along the entire length of the existing GO corridor necessitating the demolition of many houses and residential highrise buildings.
The six new SmartTrack stations would be St. Clair–Old Weston, King–Liberty (Liberty Village at King Street), East Harbour (Unilever site), Gerrard–Carlaw, Lawrence–Kennedy, and Finch–Kennedy.
[23] In the letter from the Ontario minister of transportation to the mayor of Toronto, cost pressures included escalating prices for materials and labour.
East Harbour provides significant transit connectivity between Lakeshore East GO, Stouffville GO, Ontario Line, and future streetcar service; Bloor–Lansdowne would suffer financial penalties for contract cancellation; and St. Clair–Old Weston ties into the City's St. Clair Transportation Master Plan.
This was slightly more than the 11.1 hectares per kilometre available if the TTC's heavy rail system were extended from Kennedy station to Sheppard Avenue.
However, the following issues remained outstanding:[25] A controversial part of Tory’s SmartTrack proposal during the election campaign was the Eglinton spur, from Mount Dennis to the Airport Corporate Centre in Mississauga.
(Tory and his campaign staff had planned to use the former Richview Expressway corridor to run commuter trains westwards from Mount Dennis.
Also the Tory team underestimated the technical difficulties of the large turning circle that heavy rail vehicles would require at Mount Dennis.
)[26][27][28] City Manager Pennachetti said the city would study the “technical feasibility, community impacts, and cost implications of a heavy rail line” on the Eglinton spur, including the “feasibility of any required tunnels and bridges.”[29] According to a joint report from city planners and the University of Toronto Transportation Research Institute released in January 2016, heavy rail would draw about 87,000 daily boardings at a cost up to $7.7 billion while LRT would draw more than 105,000 daily transit boardings at a cost of about $1.3 billion.
On January 19, 2016, Mayor John Tory conceded that heavy rail was not the best option for the branch from Mount Dennis to the airport.
[31] A report, titled Choices for Scarborough, Transit, Walking and Intensification in Toronto’s Inner Suburbs written by University of Toronto professors Andre Sorensen and Paul Hess, states that the worst-case scenario would be to build the Scarborough Subway Extension on the city’s approved route along McCowan Road within two kilometres of SmartTrack.
Critics claim this revised plan would prevent the subway from cannibalizing ridership from SmartTrack's branch to Markham.
According to University of Toronto academics, if the service runs every five minutes and uses TTC fares, SmartTrack could carry up to 300,000 people per day.
[32] In an October 6, 2015, letter to Toronto's city manager, Metrolinx CEO Bruce McCuaig wrote "Metrolinx and the province believe that the (city report) should reflect the scenario where SmartTrack is an incremental increase in RER (regional express rail) service, rather than an independent and parallel service that co-exists with RER."
The letter also warns that SmartTrack could entail "considerable" expense over and above the GO plans for RER, "depending on the service concept and design.
By late 2017, approval of the new Lawrence East SmartTrack station was in doubt pending a cost/benefit review by the provincial auditor general.
[19] The following table lists SmartTrack stations, both currently proposed and cancelled, along the Kitchener, Lakeshore East and Stouffville GO Transit rail corridors.