Surveillance video shows the 63-year-old victim walking right off the platform. Then you see Chris Knafelc jump down to help. He shouted to nearby passengers to tell personnel to shut down the line, and then held the man's head and neck stable until firefighters arrived.
"There are bad scenarios that could have happened here and didn't happen because a person that was unknown to our victim jumped in to that track and and saved his life," said Septa Police Chief Thomas Nestel.
Knafelc says many people have been kind to him over the years, and he wanted to pay that kindness forward.
"I can't imagine not helping somebody in that situation," Knafelc said.
The victim was hospitalized in stable condition. It's unclear what caused him to fall onto the tracks.