Didn't work for me either, but then again, I never received the post card.

Visit the Metropolitan Museum of Art, featuring the Byzantium and Childe Hassam exhibits and receive 15% off qualifying Amtrak fares to New York City this summer. Make reservations online or call 1-800-USA-RAIL and request discount code V823 (Byzantium) or V132 (Childe Hassam). Offer valid for bookings made between June 1 and September 12, 2004 with travel between June 10 and September 12, 2004.

Terms & Conditions
Discount is valid for travel in the Northeast Corridor on unreserved regional trains; all day Saturday and Sunday on Metroliners; and all day Saturday and before 1 p.m. and after 6 p.m. on Sundays for Acela Express. Travel on reserved regional trains and weekday Acela Express and Metroliners is prohibited. Other restrictions may apply.