As of August 2012, Amtrak updated its refund policy. It had previously been easy to book and cancel Amtrak train trips without any penalties. The new policy changes that somewhat.
As of August 2012 Amtrak's new refund policy varies by service as well as time. Basically, though, most tickets will incur a 10% refund fee (up to a $100 maximum) while Acela, First Class, and non-Acela Business Class have no refund fee (if canceled more than 24 hours in advance).
Refund Fee Rules by Ticket Category
First Class tickets and non-Acela Business Class tickets are fully refundable if the reservation is canceled before the train's departure time. If not canceled before the train's scheduled departure time, a refund fee will apply.
Reserved Coach and Acela Business Class are also refundable without a refund fee IF they are canceled more than 24 hours before the scheduled departure time. If it's less than 24 hours, the 10% refund fee would apply.
Canceling an Unreserved train ticket (the basic Amtrak ticket) will result in a refund fee being applied.
Advance Purchase fares are non-refundable.
Amtrak Refund Fee
If a refund fee applies, it will be 10% of the cost of the "logical trip," with a $5 minimum fee and a $100 maximum fee.
A "logical trip" is a grouping of continuous travel (such as a trip with continuous, same-day connections). Refund fee calculations may vary on the specifics of a passenger's "logical trip," so be sure to check with an Amtrak representative for full details on your specific trip.
Amtrak Refund Options
Passengers have two options for obtaining their refund. Refunds (minus the 10% refund fee, if due) will be applied against the form of payment (credit card, cash, check, etc.). The second option is to have the refund applied to an eVoucher. An Amtrak eVoucher is good for future travel, but be aware it can only be used at Amtrak ticket offices and has a limited time frame (usually one year).