I'm the original poster, reporting back after having been "bustituted" from DC to Pittsburgh in lieu of a scheduled trip on today's 29. Yes, jis ("Engineer") was prescient in predicting that 29 wouldn't leave Union Station today.
We were loaded onto four (I think) buses, leaving DC at 4:50 instead of the scheduled 4:05, and arriving (in my
case) in Pittsburgh about 10:15, an hour and a half early. No leg room, no wifi, no outlets, no view. Despite the time savings, no railfan will be surprised to hear that I would much rather have taken the train.
Amtrak staff handled the announcements and boarding with patience and reasonable efficiency. No complaints there. But I feel really sorry for the people (including families with children) who are continuing to Ohio and points west, who got no cafe car/dining car and who are now stuck waiting in Pittsburgh's grim "Amshack" with, at best, a couple of vending machines. In my dreams, Amtrak would've arranged a nice buffet for them in Pittsburgh and sent the bill to CSX.