>>did the camels possibly run 3 for this type of set up so as not to have a blind side...2nd guy, in cab, for the engineer could yell over the boiler top if there was trouble...?<<
I have read that on express runs where maintaining schedules was the primary concern, some canmelbacks were assigned TWO firemen to maintain steam pressure (much as multiple "stokers" were employed on steamships). Note that the CNJ camelback in the B&O museum is equipped with TWO firedoors!