There were two busses waiting at Albany for Boston passengers but the Boston sleeper (and I assume coaches) definitely went to NYP
Interesting. There must have been some trackwork that caused that. I think the normal procedure now is that the entire train continues to New York and passengers continuing to Boston board a dedicated (#448) Boston train. On trip I took 8 years ago (April, where I had the pleasure of wine & cheese with Gene Shalit), I recall having to leave my sleeper and switch trains at Albany to connect to Boston. That said, I seem to recall a round trip to Rochester a couple years before where they combined/split the Boston section at Albany.
Now that I mention it, I live in Boston and periodically see the train going either way with a sleeper in the consist. Perhaps it depends on sleeper availability, need for service, etc.