Riding the rails became a common means of transportation after the Civil War as the railroads moved west. The practice took off during the Great Depression. These mostly migrant workers were known as hobos. Depression hobos were often just migrants out of work. Some had hard luck lives and took to gambling or booze.
Figuring out which freight train to hop takes planning and ingenuity. Hobos might hide at a rail yard and catch a train before it starts moving. They’d better know in which direction it is going. Box cars, grainers, and gondolas are rideable if hobos catch the train on the fly. Hobos ride above, beneath, or between cars.
It is no fun riding on a coal car and then hopping off again. Hobos often form communities. They “jungle up” for dinner and heat canned food over a fire. They jump on and off of moving trains in case they are searched by the bulls at stops.
Railroad police are known as bulls. Enforcement varies. In some places train hopping is a crime. In others, bulls look the other way.
Freight train riding is dangerous. Today more hobos are ex-convicts, making violence more common.