Wang Fuchun has been a "thief" on trains since the late 1970s.

Wang is no pickpocket - long employed by the state to photograph life on the train network, he characterizes himself as stealing the images because he believes acting without his subjects' permission is the only way to capture reality.

With his camera generally covered by a coat, Wang has prowled through packed carriages snapping what he sees as his "prey" on a journey that has allowed him to trace China's modernization and great cultural change.

Now, however, he is ditching the covert tactics and has launched a project to identify the people in his old photographs. Wang, 73, wants to find out what has become of the unknowing stars of his albums.

"There's a mobile community on the train, and it has included every aspect of society; the good, the evil, the beautiful and the ugly," he says. While Wang yearns to get to know the subjects, he believes the images are powerful in themselves as historical snapshots.

A naked boy standed on a passenger seat peeing into a tin can in 1992. [Photo/Xinhua]

In a photo taken in 1992, a naked boy stands on a passenger seat peeing into a tin can.

"Little boys often used to strip off before trains had air conditioners installed," Wang explains. His photos also show lots of topless men in the stuffy compartments.