Not all graffiti is done by some punk kid with an aerosol can aimed at your back wall.
A lot of it is done with chalk or paint stick and rides the boxcars crisscrossing the country.
Hobo monikers, they're called, scrawled by men with names like Palm Tree Herby and Mournful Marvin, Frisco Jack and Bozo Texino.
"Kilroy was here"? Sure, probably to most of us. But not to Bill Daniel, who spent years hopping freight trains to document this type of graffiti and the hobos who do it.
The result is an hour-long documentary, "Who Is Bozo Texino?" which will be shown Friday night at the Southern Arizona Transportation Museum.
"I've always been interested in rail graffiti," says Daniel, 48, who lives in San Francisco and will be here for the presentation.
He hopped his first train in 1987 out of Houston, one that rolled all the way to California.
"It was beginner's luck," says Daniel in a telephone interview. "I started on a grain car. There was a little hole where you can crawl in and hide from the weather and the cops."
Asked if he ever ran into any "bulls," the railroad police, he answers, "Oh, sure. I've gone to jail a couple of times and was thrown off a whole bunch of times."
In eight years of riding, he traveled through 14 Western states, the longest trip from Seattle to Houston. With him went an old Bolex, a hand-wound 16mm camera used to shoot both the scenery and his fellow passengers.
"Most of the time I never even got out the camera. I sensed it wasn't right." Asking a hobo to record his thoughts is a little like asking for a first date, says Daniel. "It's either yes or no."
Although there were a couple of situations that "got a little crazy," says Daniel, "I managed to not be in the wrong place at the wrong time.
"A lot of people I rode with, some were just out of jail. I also rode with people who were going to be in jail soon. I rode with a guy who was murdered in camp a few weeks after I rode with him."
During the time he rode the rails, he kept a day job to pay the rent. "I was a bike messenger, bus driver, I managed a film facility," says Daniel.
While most of the hobos he met were grizzled white males, more women are showing up, especially with young men who call themselves punks, though the hobos call them Flintstones.
"One of the Flintstones, a kid named Andrew, did the banjo song for the film," says Daniel.
After years of editing, he hit the road in June of 2005, peddling his documentary from city to city. "Now I'm a rubber tramp," says Daniel, who travels in a '65 Chevy van with a speedometer "that hasn't worked in 10 years."
It was the graffiti, however, not the hobos, that got him onto the trains. "I did not have a burning desire to become a hobo," says Daniel. "The graffiti hooked me in, and that led me into the hobo culture."
Much of the documentary explores the various hobo monikers, including one Bozo Texino, a Western-hatted figure whose real-life counterpart was a railroad man in the early decades of the 20th century.
"The name has been passed down from generation to generation," says Daniel, who also documents railroad workers who mark boxcars. "Their images travel; they don't."
Tucsonan Warren Doman, who worked for various railroads over 43 years, remembers seeing Bozo Texino's moniker here and there on the boxcars.
He also remembers when railroad workers had an easy rapport with the hobos. "We used to haul them from Eloy to Yuma and over to Phoenix. We'd slow down to 10 miles an hour to let them off."
Henry Mundrick, who rode the rails as a young man during the Depression, says it was like running away to join the circus.
In between runs, he'd knock on people's doors, ask if he could chop wood for a sandwich. Long settled down in Tucson, Mundrick says he did have a moniker but can't remember what it was. Never mind. Daniel has captured plenty of others.