It wasn't a boy who fell on the tracks. It was a 20-year-old man.
And it appears that the rescuer, Mr. Autrey, acted under the most perilous conditions possible: with a train approaching, and no time to lift the person to safety, he pressed himself and his rescuee into the drainage rut between the rails while half the train rumbled over them.
My sincerest commendations to a fellow Squid.
Regarding the fatality question, BTS reports 59 fatal incidents on heavy-rail transit in 2004 nationwide. Determining how many of those are from being run over or contacting the 3rd rail requires more research than I'm willing to do at the moment. Perhaps you can try searching the
BTS website.