Silly topic perhaps, but the moniker "big boy" isn't a term original to UP's 4-8-8-4. For those that know the 1930 movie, Danger Lights, a heavy mike is referred to by the same name. Any documented earlier use of "big boy"?
Moderators: slide rules, Typewriters
(If it hadn't stuck, what would we call the 4-8-8-4 type? Double Mastodon?)According to UP, the chosen name for the F-E-E-F was to be Wasatch, so probably that.