The American rail network is optimized for freight. Outside of a few lines in the Northeast it's not really an option for intercity travel. If you want to take a train from Los Angeles to San Francisco (a 6-7 hour drive) there's only one train per day, it's expensive, and it takes twelve hours to make the trip. It's more of an amusement park ride than a way to get somewhere.

But if you want to get something shipped rail is cheap and reliable (if not particularly fast).