Having ridden a lot of Amtrak almost makes it less likely that you'd have experienced the single track problem, since quality rail experiences in the US are pretty concentrated such that someone who has good train experiences probably lives/works in an area where that is the rule. On the East coast, pretty good service arguably extends as far south as Richmond, but past that sitting on the tracks is very common. And with that you get the classic downward spiral of crappy transit. Ride a train in SC or GA, and you'll see that anyone with the money for a plane ticket has abandoned rail there.