Interesting question regarding the windows. I had no problems processing a 48 hour upgrade coupon last year at the station in PVD within 49 hours or 48.5 hours.

But this year, select members only got the 12 hour upgrade coupons, so that is what I have. I tried to get one of those processed about 14 hours ahead of time, and when I called 1800USARAIL the very friendly agent told me that the computer wasn't taking the code. He told me to call back in exactly two hours, which I did.

In terms of the coupons being capacity controlled, they are limited in terms of the FC car capacity, not how many coupons can be used on a train I think. FC acela sells out fairly often, and by sells out, I mean I think people are using the upgrade coupons. I used upgrade coupons just this past weekend for a trip BOS - PHL and then NYP - BOS. When I called to get my upgrade for the Sunday train, at first the agent told me it was sold out. I was prepared to try for a later train if it wouldn't kick my BC fare bucket too high, when she apologized and told me she was looking at the wrong train. If there are no more FC seats, you aren't going to get an upgrade.