Here’s a bit from the Utata article on him (which has more photos):
Around that same time period Brodie and his girlfriend, both of whom lived near tracks utilized by freight trains, began to fantasize about hopping trains. A year later he was out of high school and had a job, but he hadn't abandoned the dream of riding the rails. His girlfriend, however, was still in school. One day, according to Brodie, "I said 'Fuck this, man, I want to ride trains!' So I quit my job and waited around for a while and she still wasn't ready so I hopped a train to Jacksonville from Pensacola. I didn't know what I was doing, and ever since then it's been a learning process, learning how to ride trains correctly." He's been riding the lines ever since.
Brodie took along his SX-70 [a Polaroid camera] and photographed the people he met and the things he saw. He discovered—and became part of—a subculture of young vagabonds who'd had similar dreams, people who also rode the rails for the adventure of it. Not surprisingly, this community of travelers was fairly tight. "Half the people in my photographs know each other," Brodie says. "[T]hey all are in a similar age range and they’re all traveling and hanging out in the same areas, most of them, same groups. So if they don’t already know one another, they will down the road. Or they’re MySpace friends. All those traveling kids all are on MySpace, all have cell phones and all keep in touch with one another."