In some places the grades are probably too steep for trains, so we'd need tunnels or cuts or different routes through mountains and hills.

It would absolutely kick ass if I could take a high-speed train to visit other states rather than a stupid cramped and noisy airplane. Hell I'd settle for regular old slow commuter rail in my area so I don't have to worry about some jackass cutting me off because they're texting while driving, and so I can read a book while commuting.