The Quebec-Windsor Corridor is the most densely populated section of Canada; the term is particularly used in connection with VIA Rail passenger train services, analogously to Northeast Corridor on Amtrak. The principal rail routes within the corridor are:

• Quebec City - Montreal (services to the south shore opposite Quebec City are not considered Corridor trains)
• Montreal - Ottawa
• Montreal - Brockville - Kingston - Belleville - Toronto
• Ottawa - Brockville - Kingston - Belleville - Toronto
• Toronto - Aldershot - St. Catharines - Niagara Falls, Ontario (with a joint VIA/Amtrak service, the Maple Leaf, continuing Buffalo - Albany - New York)
• Toronto - Aldershot - Brantford - London - Windsor, Ontario
• Toronto - Guelph - Kitchener - London - Sarnia (with a joint VIA/Amtrak service, The International , continuing Flint - Battle Creek - Chicago)

(Aldershot station is in Burlington, but also serves passengers for Hamilton.)

For the most part these are all operated as independent routes, but a few trains continue beyond Toronto (not to the next main destination, but services such as Ottawa-Aldershot) or cross between the two routes running west from Toronto through London.

Services vary from two trains a day on routes such as Toronto–Niagara Falls up to a maximum of six day trains and one overnight train on the Montreal–Toronto run, much of which is also shared by Ottawa–Toronto trains. As well as the most frequent long-distance train service in Canada, this route is also the fastest, with services operated by Bombardier LRC trains at up to 160 km/h (100 mph).

Several plans have been proposed over the years for the creation of a high-speed rail line in this corridor. Some of the most recent ones are based on a variation of the Acela trains developed by Bombardier for Amtrak while others are based on the new JetTrain prototype turbine locomotive also developed by Bombardier.