There is apparently another operational reason Amtrak would prefer sleeps on 66/67/69 - Right now 448/449 ends up with a single sleeper in BOS, which means there's no real way to provide a protect. By having at least two trains that run out of Boston that have a Viewliner, if you do end up with a protect there, you're protecting two trains not one, or if need be you can cancel one and move it to the other train, etc.
But that said, I'm all for bringing back this sleeper.
(of course if I had my druthers, I'd prefer something that split/joined in NYP. Say take 66 and put a sleeper at either end, when at NYP break the train and run it north to Albany and the other end East to Boston.
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