It's something transit officials say you should never do, but three children were caught on camera riding on the back of a subway train in Manhattan. NY1's Lori Chung filed this report.

“I was shocked, basically," says Sean Futterman.

The sight of teenagers joyriding on the back of the train stunned Sean Futterman during his evening commute this Monday so much that he pulled out his camera phone to capture what he was seeing, after he says concerned adults spoke up.

“They were all basically screaming at the kids to get off, to get off the train, that it was dangerous, they were going to get killed. I, of course, did the same and they started cursing at us," Futterman says.

It happened Monday during the evening rush at the 96th Street station.  Futterman says the kids starting hopping on the back of an uptown 2 train that had plenty of space inside.

His first thought?

“My son in ten years doing the same thing being in that horrible, dangerous situation," Futterman says.

Other commuters at the 96th Street station were stunned themselves to see the photo of the foolish stunt.

“That's not good," one person said.

“It's sad. Why they do that, I don't know why. I wish they wouldn't," another said.

"It doesn't take much to fall off a train so hopefully they'll learn somehow that that's not the thing to do," said another.

Futterman says he and other adults in the station tried to find a police officer or Metropolitan Transportation Authority worker to intervene.

“They were calling for the conductor, nobody was coming out, nobody was doing it and then the train took off," Futterman says.

It took off into the darkened tunnel with three kids hanging on the back. Now, Futterman's hoping other parents take note of this image and discourage their kids from taking a chance like this with their lives.

The MTA, obviously, disapproves of this kind of thing. There are signs everywhere throughout the subway system that discourage going anywhere near the tracks. Everyone we showed this picture to was just relieved this did not end in tragedy.