Eleven-year-old bakery worker Glenn Dungey. Oklahoma City, Oklahoma. April 1917. Photograph by Lewis Wickes Hine. View full size.

Swipin’ coal from the freight yards. Oklahoma City, Oklahoma. April 1917. Photograph by Lewis Wickes Hine. View full size.

Trapper Boy, Turkey Knob Mine, Macdonald, West Virginia. Boy had to stoop on account of low roof, photo taken more than a mile inside the mine. October 1908. View full size. Photograph and caption by Lewis Wickes Hine.

Vance, a trapper boy, 15 years old. Has trapped for several years in a West Virginia coal mine at 75 cents a day for 10 hours work. All he does is to open and shut this door: most of the time he sits here idle, waiting for the cars to come. On account of the intense darkness in the mine, the hieroglyphics on the door were not visible until plate was developed. September 1908. View full size. Photograph and caption by Lewis Wickes Hine.

One trapper's description of the job, which paid about $1.60 a day:

Trappers were responsible for opening and closing the underground ventilation doors. In those old mines, they had a system of doors between sections to direct the flow of air. Air was supposed to go up the main haulage and back to the fan. So a trapper sat all day by his door with an oil lamp on his cap. There was a "manhole" - a shelter hole in the wall by the track. The motorman would blink his light at me, and I'd throw the switch and open the door for him. Then, I'd jump into the manway until he was past, and run out and close the door. A trip would come along about every hour. Was I bored or lonely? Well, it was my job.

Santa Fe R.R. yard at night, Kansas City, Kansas. March 1943. 4x5 Kodachrome transparency by Jack Delano. <View full size. to see the light trails made by the yard workers' torches in this time exposure, as well as a phantom number (3167, at right) that must have been on a train that paused in front of the camera.

Santa Fe R.R. locomotive shops, Topeka, Kansas. March 1943. View full size. 4x5 Kodachrome transparency by Jack Delano.

On streets near Daniel Mill. Lincolnton, North Carolina. November 1908. Right hand boy is Dan Biggerstaff. 10 years old. Has worked three years. Goes to school now (he says). Left hand, John Erwin. Said 11 years old. Has worked nights. Photograph by Lewis Wickes Hine. View full size.