HAVERTOWN, Pa. (CBS) - Seven people were injured in a train accident in Delaware County Friday night, according to SEPTA officials.

A Norristown High Speed Line train in Havertown became uncoupled a little before 8 p.m. The train, which was headed to the Norristown Transportation Center, had just left the Penfield Station when the two cars separated; the end car struck the other, then reattached.

Six people were treated at the scene; a seventh person was taken to the hospital for observation.

After some delay, the Norristown High Speed Line resumed normal service.

Investigators are looking into the cause of the accident.