I think size should matter more.
In USA/Canada we end up with population pimples with little in between. This is perfect for HSR, since there are very few required stations between primary cities.
Ottawa-Montréal, for example, is ~200km apart with no major centers in between, so an HSR can cross that distance with no stops
Toronto-Montréal is ~550km apart, with one possible stop in Kingston if the train splits for Ottawa. Again an HSR could make great time here. With the TGV’s 270kph station-station time, it would be 2 hours, slightly faster than flying + security (2h10-2h30) and less than half the driving time.
I’m knot as knowledgable about US geography, but I’m positive there and many city pairs like this on the east and west coasts.
This is perfect for travel but not passenger load which is what makes a transport system economical. Rail costs several million dollars per kilometre, so a Toronto to Montreal would cost at least 500 million, closer to a few billion. And if it travels through low density land you won’t be getting many additional passengers except those that actually live in Toronto and Montreal. This is why HSR is in densely populated areas like France or Japan, or China. There is an actual large passenger load that makes the investment worthwhile. An even easier-to-see example is that city driving is much slower than on highways, if point-to-point travel time was really the function of public transit then intercity travel would be prioritised not the much larger and more economical street stops that every public transit system uses.
so a Toronto to Montreal would cost at least 500 million, closer to a few billion
$3 billion on 1.7km of Gardener Expressway repair. $3.6 billion for Turcot interchange replacement. No one bats an eye at those costs.
passenger load which is what makes a transport system economical
Toronto-Montréal is the busiest domestic flight route, followed by Toronto-Ottawa. Add Chicago and New York to capture the two busiest routes between the two countries (both in the top 20 international flights). Plus however many bus, train, and drive.
Edit: just plugged 15 Nov into Google flights; there are 46 flights from Toronto to Montreal that day (Pearson and Island combined).
