From my experience, the "sleepers" are always in front on the CL. And of course other trains as well, I don't have a list.
Question, why would Amtrak EVER position the "sleeping car" in the front of the train, rather than the back where it is quieter? And should I not ask the question because hey, coach PAX have to sleep too?
Seems that if you offer a product called a "sleeping car" with a bed etc. and charge a premium price, it would make sense to place it in the quietest possible location (rear of train).