(Newser) – Most days, recovering drug addict and ex-con Christopher Knafelc has plenty to regret. But not Thursday, when he didn't hesitate to save the life of a perfect stranger. As the AP reports, Knafelc was sitting on a bench in a Philadelphia train station when he saw a man in front of him fall to the tracks below. Knafelc immediately jumped down to help him, stabilizing his head and yelling to bystanders to stop any oncoming trains until firefighters arrived. "It did help reinforce that I'm a good person," says Knafelc. "I questioned that a lot because of my colorful past."

"I think by doing this good Samaritan deed he's kind of surprised himself," says a spokeswoman for the Southeastern Pennsylvania Transportation Authority. "It's amazing. This incident may be the start of really good things for him." Knafelc thinks it's just paying back a little of the kindness he was given when he was down and out. "I'll never be able to repay them, financially or any other way," he says of family members. "The next best thing I can do is pay it forward." (Read more Christopher Knafelc stories.)

