Did the GG1s have a fireman back in the day and if so, what were his duties?
As far as I know, there was a fireman on every GG1 until the very end. In addition to tending the train heat boiler, his most important duty was calling signals and blowing for grade crossings. This doesn't sound like much but the engineer's visibility to the left front of a GG1 was absolutely terrible. On a long curve to the left, the engineer was literally flying blind. Knowledge of the railroad helped with grade crossings and cab signals were great, but neither was as good as an alert eyeball.
I don't recall any specific ones, but I'm sure there were also situations where a ground man could not be seen from the engineer's seat. He might have been able to move to a position where the engineer could see him, but the fireman relaying his signals across the cab was a whole lot more convenient.