Be careful when booking parties of more than 1 passenger. If there are not enough low priced seats or rooms, as the case may be, all of the passengers will be ticketed at a higher price. If you book a party of 8, and there are 2 Saver seats and 6 value seats available, the party will be charged the high Flexible fare. I'm not sure what the computer does if there are only 7 of them available!
With Sleeping rooms, it's worse. If you book a party of 2, and there is only 1 low priced room available, you will be charged a higher price, even if you take just 1 room! Check out the Cardinal, which seems to have just 1 Sleeping Car. There are NO roomettes at the lowest bucket, 1 at the 2nd lowest, and 2 at the 2nd highest bucket. There are only 2 Bedrooms on that train, so a party of 7 or 8 is always told that there are no accommodations available if Bedrooms are chosen. (14 days before departure, the Handicapped Room is changed to a Bedroom if unsold, so a party of 5 or 6 might get lucky them.)
The Lake Shore Limited's New York section, which seems to have 2 Sleeping Cars, has 1 roomette at the lowest bucket, 3 at the 2nd lowest, and at least 4 at the 2nd highest bucket.
Probably a solution is to book for 1 person, and then call on the phone to have an agent manually add the 2nd passenger to the room on a separate rail ticket. An excuse could be that the other person was not originally traveling, or wants to pay separately.