Roger, the photo you just posted of F3 set #52 at South Hammond IS of the two units that would become #65A and B later in the year. Neat photo BTW--hadn't seen it before. Also beautiful model of #65.
Immediately after the disastrous Ash Grove wreck, EMD loaned an A-B-A demonstrator set to the MONON, which MONON bought sometime later (fall or winter 1947-48) to replace some of the totaled units. The A-units became dual-purpose set #85 (they had steam generators) and the B-unit #65C, (it also had a steam generator). It was teamed with the #52 set to become the new A-B-A set #65. Actually, it's even more complicated/confusing that that, but this is how it ended up.
George, until at least the last half of 1949, none of the A-units carried "A" or "B" on their numberboards, since the MONON up until about that time treated each A-A or A-B-A consist as single 3,000 or 4,500 hp locomotives. The was a common practice among railroads that were dieselized early, partly to get around the Brotherhood's manpower requirements back then. Plus, by then, it had become obvious that for better flexibility it was much more economical and efficient to break up such "sets" into their induvidual units and mix-and-match them as needed.
