Quote:
Originally Posted by The Chemist
Personally, I much prefer HSR to flying. I'll take the HSR anywhere it goes here in China (some routes are up to 9 hours long, such as ShanghaiKunming or BeijingGuangzhou). I travel a lot for business and I prefer the train because a) you can arrive at the station only 30 minutes prior to departure and have no trouble catching your train b) the train is almost always on time, which is more than can be said for many domestic flights c) the seats, even in second class, are much more spacious than an airline seat d) can use phone and have full access to internet for the entire journey.
Passenger loads on flights on almost every city pair in China connected by an HSR route that takes less than 5 hours from city to city have dropped dramatically because so many people prefer to take the train.

Let's run just a little further with your 5 hour limitation. It's 789 miles following I80 between New York City and Chicago, and 1285 miles following I95 between New York City and Miami.
To reach Chicago in 5 hours, it would have to average 158 mph. To reach Miami in 5 hours, it would have to average 252 mph. So, off hand, Chicago looks doable while Miami certainly isn't.
Note, that's an average speed, not the maximum speed. Some simple math to bring that point home. In one hour a train running at a maximum speed off 200 mph travels 200 miles. 200 miles is a long way to go without stopping at intermediate stations. If the train loses 6 minutes (10%) at intermediate stations, it only travels 180 miles, if the train loses 12 minutes (20%) at intermediate stations, it only travels 160 miles. We're quickly approaching the average speed sweet spot of 158 mph. And it's impossible for the train to reach Chicago in 5 hours if the train loses 18 minutes (30%) every hour.