From another thread:
<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by Reindeerflame:
For much of the fall, Amtrak is now offering a 5% discount for booking on its website, with the added twist that the discount can be used on top of other discounts that the traveler may use (such as the 15% senior discount or the 10% AAA/NARP discount). There are some holiday blackout dates.
As usual, the discount only applies to the basic coach fare ("transportation") and does not apply to sleeper or business class "accomodation" charges.</font>