The Southeastern Pennsylvania Transportation Authority said the crash happened around 12:15 a.M. Today.
An inbound Norristown High Speed Line train crashed into an unoccupied, parked train at the 69th Street Terminal in Upper Darby, said SEPTA spokeswoman Heather Redfern. SEPTA said 33 people aboard the train were injured.
In an early morning news briefing, Upper Darby Mayor Nicholas Micozzie said at least four people suffered serious injuries.
"The conductor is in the hospital right now, I can't release his condition," Micozzie said.
The cause of the crash remained under investigation. No other information was immediately available.