This is a bit off the wall, but here is my guess. Way back when the whole shebang started, nothing was built for the railroad parsay. Everything was taken from earlier useful designs, such as the early stage wagons used on many a first line. There is a barrel called a hogs head barrel, I think thats right. And now if this is right, then somehow, the barrel got mounted on the engine and then somehow, the engineer was in such close proximity that it became easier to call hime th hogs head because he was near or on the hogs head. Well, thats my guess, I know it is wrong because I did absolutely NO research, and usually when I don't do my homework, I end up being wrong. Enjoy
My take was that locomotives have long been called "hogs", Hence Hog Head or Hogger(used on the BNSF) Another sort of derogatory term for engineer on the BNSF is "Greasehead". CT
Where is Watash when you need him? I'm sure he would know how the term got started ... he probably started it
Charlie came the closest I think. I have heard several reasons, none really good. One was that the engineer absolutely HAD to make his run "On The Advertized", (be on time when his train arrived at its destination.) The expression when sending him off on his run, was: "Root Hog or Die!" Meaning: "Git her from here to there on time or your out of work!" "Lean on that throttle and make her squeel!" "You got 38minutes to make it and 7 are already gone, now git!" Those are not the kindest words to us friendly old timers. It has been said our feelings might be wounded. The grunting, snorting, and nashing of the teeth that follows does remind one of an angry hog! Another possible reason for the name refered to the male Hog who was the leader followed by his sow, who was followed by all the little piggies in a row through brush, brambles, and thorn bushes. The Bore would lead the way, breaking a trail easier for his family to follow, hence, the connection of the engineer who would lead his entire train as did the Hog at the head end. Several others loosely linked the steam engineers to the temperment of a wild bore, short tempered, grouchy, stuborn, wont back down from a fight, and highly territorial, who's decision is always the right one, fully expecting and intending others to follow. ergo: "The Head Hog". How would I know? I'm a peacable, sweet, gentle, softie, ain't that right Art? (WATCH IT!!)
Have also heard it said the name comes from people saying the front of a steam engine looks like a hogs snoot, hence "hogger."