King Coal by Upton Sinclair

There was another way, Old Mike explained, in which the miner was at the mercy of others; this was the matter of stealing cars. Each miner had brass checks with his number on them, and when he sent up a loaded car, he hung one of these checks on a hook inside. In the course of the long journey to the tipple, someone would change the check, and the car was gone. In some mines, the number was put on the car with chalk; and how easy it was for someone to rub it out and change it! It appeared to Hal that it would have been a simple matter to put a number padlock on the car, instead of a check; but such an equipment would have cost the company one or two hundred dollars, he was told, and so the stealing went on year after year.

"You think it's the bosses steal these cars? " asked Hal.