A few of us glanced up sullenly from our papers and iPods, all of us in a hurry to get moving.

A new voice came on the intercom, the voice of the station master. "Hold on, Chris. Keep your brake on, there's a red flag. There's a kid down on the track! He got squeezed off the platform. Keep your brake on!"

We all looked around at each other, then, until the conductor spoke again.

"What was that? I couldn't hear you. I've got a timetable to keep."

The doors slid closed with a chime. We were up on our feet, pounding on the doors and windows, shouting for the conductor.