For any railroad postal enthusiasts, here is the souvenir cover I made up for 844's visit to Parsons, Kansas stopping on "The Valley Eagle" Heritage Tour, Cheyenne to Harlingen, TX and return. This was on April 7, 2009, with Nystrom as the engineer, his autograph is on the envelope. There were six such souvenirs made up.
http://www.qsl.net/kg0yh/UP844_04072010_67357m.jpg Front side
http://www.qsl.net/kg0yh/UP844back.jpg Back side
I have some pictures of that event as well, if anyone is interested, can post links.
RPO (Railroad Post Offices) special event stations, railway postal markings; Amateur Radio.
My current research project is at
http://tinyurl.com/McD2011, re: McDonald Territory Secession Attempt