I have not, but a friend of mine did that last November.
He thought it was great. Slept most of the way down and was refreshed and ready to ride when the train pulled into the station. He had no complaints.
I looked into this a while ago,, (yrs) it was a expensive proposition, especially if you want a room on board to sleep...
If not then you sleep on the seat..(if there is no one else maybe it's ok)
let me look for the link... Amtrak