Getting retroactive credit
 

How strict is AGR with the "time of purchase" rule? My mom made reservations several weeks ago for herself, my father, my brother and I to attend a memorial service for her mother, held this past weekend. I called reservations a week ago to have my AGR# number added before the trip. The rep said she did it; the number did not come through on the boarding passes. I am really out-of-luck on this? Or will they likely give me the points if I provide the res and ticket info as requested?

You can request retroactive credit as long as it is within 30 days of your travel date. If you go to the Amtrak rewards site and follow their instructions, you should have no problem getting credit.

Kind of a narrow window - they ask you to wait 3 weeks before requesting, but not more than 30 days!

Yes, but the 30 days is in a situation where your number was not on the ticket. If your guest rewards number is on the ticket I believe you have 90 days to request missing points to be added to your account.

Here are the rules:

How do I receive credit for tickets purchased without using my membership number?

To request credit on a previously purchased ticket, send the ticket stub with your name and membership number to: Amtrak Guest Rewards, P.O. Box 1762, Minneapolis, MN 55440. Requests must be received within 30 days of travel. Retroactive points will not be granted for travel occurring more than 21 days prior to enrollment.

If points are missing where your ticket was purchased with a rewards number, you have 90 days to request credit. In your case, you know the points won't show up since you didn't give them your number when you bought the ticket, so you don't really need to wait 3 weeks.