I posted a response to your question a couple days ago (in the Amtrak/Bolt Bus question):
i too would guess west - my wife took the train north a few months ago and she remembers being assigned a car but wasnt sure if she was given a specific seat
Yes, they assign seats, not just cars. You get the seat assignment as you line up to board. If the train is not very full, they do try and give everyone a window seat, and on the scenic side. You can also just ask for that:)
Thanks so much!