Christopher Knafelc, 32, was sitting several yards away at a North Philadelphia subway station on Thursday afternoon when he saw what appeared to be a man tumble off the platform.
Of all the people standing around, some just feet away, Mr Knafelc was the only one to not only rush to his aid, but immediately jump down beside him - a man he didn't know.
'I jumped down. He was in pain. He was in agony,' Mr Knafelc said.
'I knew I had about five to 10 minutes until another train,' he said. 'I told the guy in the booth to suspend southbound trains. I already had a plan in mind if a train came to roll underneath.'
As they waited for rescue crews to arrive, with the train traffic securely halted around them, he says he tried to keep the man's head and neck stable in the meantime.
'I kept him talking. I said are you all right? What hurts? He didn't thank me but I know he was thankful,' he told CBS Philadelphia.
Oct 7, 2013
Man aid stranger who fell in Philidelphia subway tracks.