they exist, but arent really used. the us is much bigger / less dense intercity. going across the coasts is six hour flights but days(4ish i think) by train a

they exist, but arent really used. the us is much bigger / less dense intercity. going across the coasts is six hour flights but days(4ish i think) by train and significantly more cost, with not many cities in the middle that people stop at. too few people would use so theres no motivation to make it faster. where it works decently well is northeast, because the cities are very close together(dc,philly,nyc,boston). but it's usually much more expensive than driving/bussing and takes roughly the same time.