A spokeswoman for the Southeast Pennsylvania Transportation Authority said William Clark, who is believed to be 25 to 30 years old, was arrested Thursday, KYW-AM, Philadelphia, reported.
The attack late Tuesday afternoon was not publicized and police did not release surveillance camera video until after the arrest. SEPTA Police Chief Thomas Nestel said the man depicted in the video was wearing an unusual jacket and investigators feared he might throw it away if he knew he was a target, the Philadelphia Daily News reported.
"It was so distinct that we tried to keep the description of that jacket in law-enforcement circles because it was our best lead on clearing this," Nestel said during a news conference. "With our partners in the Philadelphia Police Department, we increased the number of officers out on the platform in our stations and there were many people looking for this person."
Police said the man asked the woman for a light and when she obliged grabbed her, hit her several times and then dragged her across the platform. He left with her cellphone.
The victim, 23, was able to climb back to the platform. She had only minor injuries.
She told KYW she was grateful no train pulled in while she was on the tracks.
"I started trying to fight him back as much as I could," she said. "After it was over, the first thing that popped in my head was my son."