Originally Posted by Points Scrounger
Sure, Tripper. You hand the completed AS form to a conductor on the Cascasdes or Coast Starlight train for processing. Forms are available at staffed stations (Seattle, Portland, etc.) and onboard the Cascades train. Coast Starlight is eligible, but I wouldn't be so confident they stock the forms. If you can't find any, or they don't post to your AS account within a couple of months, you can send photocopies of your boarding apsses directly to Mileage Plan for credit.
The two programs are independent and not coordinated. The AS program predates AGR but was never phased out. Fortunately, Amtrak is not an airline. Participation in the AS program on Amtrak is rather cumbersome, with manual submittal of forms for each trip required, rather than placing a number on one's ticket. But, we're not complaining. If Amtrak were asked to modernize this, they would probably discover that the program is still operating, and might then end Amtrak's participation.