One can also book seats in night trains -- which I've never understood, btw. That only seems logical as a last resort when you need to be somewhere but got no money to get there, when you're planning to sleep the day away at your destination, or enjoy the prisoner's dilemma where you hope the potential co-passenger decides not to "defect" (buy a ticket) such that the seat next to you is free and you can lay down and sleep at night. But anyway, more on topic, I am wondering if the laying down is what you mean or something else in addition
The seats on long distance Amtrak trains are not at all like you're imagining.
Think of them as more like a lounger/recliner. Not the most comfortable you'll ever sit in, but it's reasonably easy to sleep them in, and even more so if you're young. Someone next to you matters only if they snore or smell.
One can also book seats in night trains -- which I've never understood, btw. That only seems logical as a last resort when you need to be somewhere but got no money to get there, when you're planning to sleep the day away at your destination, or enjoy the prisoner's dilemma where you hope the potential co-passenger decides not to "defect" (buy a ticket) such that the seat next to you is free and you can lay down and sleep at night. But anyway, more on topic, I am wondering if the laying down is what you mean or something else in addition