This time was adjusted since bringing the train back after COVID. There is limited areas the train can pass and I guess they decided leaving later is better.
I don’t think taking the train south is worth it, you spend your morning waiting in line because you don’t have booked seats (and you want a window), and then you sit on a train the whole day.
But for going north, you arrive to Moynihan Train hall in NYC 30 minutes before to print and stamp your ticket for going into Canada, as well as getting your bags tagged. Then you can wait in a lower mezzanine and go down to Track 8 where it normally sits there early (you can go before they announce it, and just ask the employee to confirm it’s the train to Montreal), allowing you to board before anyone else. Then once you reach the border, depending how busy your train is, if there are less people then you can arrive sometimes an hour and a half early! It’s not faster than the bus but way more comfortable and very pretty depending on the time of the year.
A night train however would be perfect for how long this takes…