Bought and thoroughly read and re-read the Spring 2015 Classic Trains magazine that covers the history of EMD's masterpiece.
So questions to you RR dieselophiles:
I did not see any reference as to why these were named F units. I know there were the E unit predecessors so F makes sense. But what were A,B,C,D units, as I don't recall reading any units with these letters? I know there were diesel "A" unit cabs, "B" unit boosters and several RR used "C" for a trailing cab unit.
And finally, why was the first F unit #103 named as FT series and not F1. What did T stand for?
Or maybe just point me to an internet source for the answers.