It happened shortly before 7 a.m. Officials said all trains will board on the outbound platforms between Neshaminy Falls and Noble Stations.
There has also been no word on why the person was on the tracks.
Emergency personnel is on location and will determine when service can resume, according to SEPTA officials.
Alternative service suggestions are available using the SEPTA Trip Planner.
This is a developing story and will be updated when more information becomes available.