Midtown corridor

The Midtown corridor refers to three new GO Transit services in Metrolinx's regional transportation plan for the Greater Toronto and Hamilton Area, The Big Move. The first is a Crosstown line from Dundas Street to the former Canadian Pacific North Toronto and Leaside stations in Toronto. The second and third segments would extend east from North Toronto and/or Union Station: the Seaton line to Seaton, and the Locust Hill line to Locust Hill.

GO Transit has contemplated a Midtown corridor since the 1980s as a contingency plan once capacity at Union Station became constrained, making North Toronto an alternate station for Downtown Toronto. The major barrier to these plans, however, is the fact that the Midtown corridor is composed of existing rail lines owned and actively used by Canadian Pacific Railway (CP) as its main freight line between Ottawa, Montreal, London and Windsor. CP has been reluctant to provide capacity to GO Transit on its tracks, and the Milton line (which runs along CP tracks to the west) only came after considerable negotiations, and an investment of hundreds of millions of dollars.

All three lines in the corridor were listed under the 15-year plan of The Big Move upon its publication in 2008. However the Havelock line was moved to the 25-year plan on February 14, 2013, because of "very modest ridership potential and significant infrastructure and operational challenges related to the Agincourt rail yards."