Green’s Dictionary of Slang

(US tramp/railroad) a locomotive engineer.

1911		Wash. Post 10 Dec. 4/5: An engineer is [...] a ‘hogger.’.
1914		‘The Hoghead’s Dying Request’ in N. Cohen Long Steel Rail (1981) 369: A hoghead on his deathbed lay, his life was ebbing fast away; / His friends around him closely pressed to hear the hogger’s last request.
1927		C. Sandburg ‘The Dying Hogger’ in Amer. Songbag 186: [as cit. 1914].
1930		‘Dean Stiff’ Milk and Honey Route 27: It is not necessary for the hobo ever to meet the engineer of the train, known among our kind as the ‘hogger,’ or ‘hoghead’.
1931		‘Casey Jones’ in Irwin Amer. Tramp and Und. Sl. 214: Casey Jones was the hogger’s name.
1936		C. Sandburg People, Yes 101: An old hogger.
1945		F.H. Hubbard Railroad Avenue 193: In the cab, a home-guard hogger addresses a boomer brakeman.
1952		in Fenner Throttle 14: Frank, the youngest hogger on the line, was taken down a peg or two [HDAS].
1991		(con. 1920s) O.D. Brooks Legs 166: The boxcar gave a lurch and we knew the hogger had backed the road hog onto the train.