Welcome AMPiette!

Most (if not all) promo codes are blacked out around major holidays (Memorial Day, July 4, Labor Day, etc...), and some minor holidays (like President's Day). During Thanksgiving, they are usually blacked out for the entire week! (This is one of the busiest times for Amtrak.) And around the Holidays, the blackout days usually run something like December 14 or 15 until the beginning of January.

If your travels are within any blackout period, the best you can do is one of the "regular" discounts (like AAA or senior).

A thing to note is that - since a round trip on Amtrak cost the same as 2 one way tickets - you may want to book 2 O/W trips instead of 1 R/T trip. This is especially true if 1 date is in the blackout period. (Example - if your trip is leaving Sunday and returning on Wednesday, and Sunday is blacked out, book 2 O/W trips!) That way, you could use the AAA fare O/W and the applicable promo code the other way! If you try to put in the code when O/W is blacked out, you will get an error message and a "non-discounted fare"!

I personally would rather have O/W being 10% off and the other as 20% or 25% off, instead of both ways being -0-% off!