Paintcan Harry was really good at what he did. Tagging. A buddy of his had an engine he used to do side work the major railroads wouldn't. Harry painted Railroad Police on a car and had his buddy haul him all over the county. Harry's buddy would drop the car and Harry would wander around tagging other cars. No one ever bothered him.
(This is, of course, a fictional story. Harry didn't have a friend with an engine.)