Amtrak Monthly Pass / Amtrak Commuter Pass
A monthly Amtrak Pass, or as Amtrak calls it a "Multi-Ride Ticket", can be purchased at http://tickets.amtrak.com/itd/amtrak/MultiRide/
- One Monthly Ticket, valid for unlimited travel for an entire calendar month, between Philadelphia 30th Street Station (PHL) and New York Penn Station (NYP) as of January 2009 is $1,152.00.
- One Ten-Ride Ticket, valid for ten rides within a 45-day period (same station pair/effective date as above), is $512.00.
There is no monthly or multi-ride option for the Acela. Acela tickets are full price and must be purchased for each individual leg of your trip. Neither of the above ticket types can be used on the Acela, and they'll kick you off if you try and claim ignorance. The Acela is the Amtrak money maker and the conductors enforce that you have a valid Acela ticket.
So the monthly and 10 trip is what Amtrak offers for regular riders. There is no "commuter pass" or any other viable low cost option for regular Amtrak riders. Amtrak seems to discourage commuters with its pricing in my opinion, but that's the way it is and since Amtrak had record revenue and ridership in 2008 I don't think this will change in the near term.
I get this question often and wanted to post this information as it is kind of buried on the http://www.Amtrak.com site.