Comment by xp84

You still need all those things for a high speed train. The only reason it’s a little less today is that almost nobody takes passenger rail.

Keep in mind these old downtown stations built in 1900 won’t be able to handle the kind of passenger counts that would “need” to be shifted from the airports, so don’t delude yourself into thinking you wouldn’t need big train stations built in the outskirts, crowded and irritating to get to, like we have with modern airports.

Your day trip thing sounds even more confusing. That itinerary that’s “near impossible” with fast flight becomes more impossible with trains that take 2-3x longer. Also, sleeper train tickets are incredibly expensive compared to coach, because of how much space they take up and the cost of upkeep for these little suites. They’re always going to be expensive, like the redeye flight on a lie-flat bed. So again, no different than what we have today, just much, much slower and less accessible to the masses.