And if tomorrow's Lake Shore is sold out and no coach seats are available, will sleeping car passengers be given another free night in a hotel or will they be bused?
On our trip in 2014 we arrived in Chicago on No. 6 around midnight or shortly after. I think that most connecting passengers took advantage of Amtrak's offer to provide hotel rooms. However in speaking with a number of the passengers at the hotel the next morning I found that a number were not planning to continue their journey on Amtrak but were planning to go to the airport or rent a car.
We were accommodated on the next day's Lake Shore but could only get a roomette as far as Schenectady on that train instead of through to Boston as our original reservations indicated. 48 and 448 were horribly late so it was another night on a bench in South Station waiting for the first bus to Maine in the morning.
But as the Amtrak apologists like to say, we received our transportation to our Amtrak destination so we have nothing to complain about. (And we did receive a small pittance for losing our roomette between Schenectady and Boston.)
P.S. Sorry, I realize now that I had not answered Eric's question although I intended to. I would think that if the next day's train was completely sold out that under Amtrak's guaranteed connection policy, they would be responsible for another free night in a hotel. Maybe someone has actually had this happen and knows for sure.