Isn't this about as opposite of FlyerTalk you can get?

I assume you're taking Amtrak. Keep in mind, that Amtrak long-distance trains can be notoriously late because the slow freight trains which often share your rail (Amtrak doesn't own those tracks) will slow you down. Maybe you'll have to wait for them to cross or you'll be behind them. I would refrain from putting on eyemakeup when a train is entering or leaving a station. But when the train is moving quickly? You'll be fine.

The only overnight train I ever took was on Rail Canada from Jasper to Vancouver. I remember a private washroom but not a shower.