B&O Owned 38 FA2's and 21 FB2's..
(No FA1's or FB1's)
Not sure about passenger service for some of them..
found a few internet guesses that "some might have had steam generators"..
but haven't been able to confirm that..
The numbering is a bit convoluted..
Looks like originally an ABA set would have been numbered something like:
825 (first A unit)
825x (the B-unit)
825A (the 2nd A-unit)
There were also (perhaps later, or with different orders) some B, D, and AX suffixes in the mix..
individual units could have been re-numbured several times, even when they were still in the 800 series..
later still, they were renumbured in the 4000 series.
To try to work it out, here are some rosters: