Call Amtrak at 1-800-USA-RAIL or visit Amtrak's web site in the "Resources" section below. On the web site, you can book your train reservations via Amtrak's Fare Finder. You can also navigate the site if you have a PDA, Blackberry or other handheld device. The trip from Penn Station in New York to Central Station in Montreal takes approximately 10 hours.
If you ordered your tickets online or by phone, pick them up at a ticket agent or at one of the Quik-Trak kiosks that can be found at many Amtrak locations (you'll need to enter your reservation number). If you've booked your trip far in advance, you can also request that your tickets be mailed to you.
Board the Bonaventure Metro or McGill Metro, located just outside Central Station, to get to your destination in Montreal.
Ride the commuter rails from Central Station. Central Station is Fare Zone 1, one of two downtown terminals for the commuter train system.