A postscript on the Adirondack. As of September 14 the Adirondack was back in service; it left Montreal Gare Centrale on time, which turned out to be 90 minutes before my train from Nova Scotia, The Ocean, arrived there. I'm glad I had a Plan B, which was VIA's "Corridor Service" train to Toronto Union Station, connecting onto the GO commuter train service to Niagara Falls, ON. I overnighted at a refurbished Ramada Inn just north of the station there, and then took Amtrak's Maple Leaf the next morning to Rochester, renting a car there (there were no rental cars available in Buffalo), touring western New York, and then returning the car, getting back to the station and taking the Lakeshore Limited to Cleveland (arriving there about an hour late).

I have no complaints whatsoever. I had a great experience on VIA and would highly recommend it to anyone who loves rail travel.