Some runaways are drawn to Bombay's glitz, land of Bollywood and shining shopping malls. Still others become separated from their families on a train and simply ride until the last stop.
At Mumbai Central, representatives from Saathi, another nonprofit organization supporting homeless children, provide the young residents with a benevolent adult presence. Although there are group homes available, station kids fear institutional life, says Washington Gupta, a Saathi outreach worker.
"In an organization, they have to follow some rules," Mr. Gupta says. "These guys want to go to the films, see adult movies. They want to be free."
But being free has a high price for these children.
Santosh and Ketn, two of the station's youngest inhabitants, wander the platforms together. Both 10 years old, the pair look impossibly small in the immensity of the station.
Santosh arrived in mid-May. Wearing a tiny military uniform and a serious expression, he is vague about his origins, saying only that he came to Bombay to work. During the day, he sweeps trains with a bundle of hay and asks for handouts.
Ketn carries a shoeshine brush and a tin of black polish. He says he moves freely among the city's rail stations, avoiding the first-class coaches, where passengers are intolerant of beggars.
Do they ever play, have fun? The boys look at each other and shake their heads. No.
The crowds at the stations provide the children with anonymity and a chance to make a living through handouts and odd jobs, but they are also filled with dangers.
A brothel agent, labor recruiter, or other predator usually approaches children within 15 minutes of their arrival, according to Saathi.