The accident happened around 10:30 a.m. Thursday in Norwood, Pa., about 10 miles south of Philadelphia.
Amtrak officials say an Acela train running from Boston to Washington, D.C., hit two people.
Authorities say they were teenagers.
Interboro School District Superintendent Nancy Hacker says the two girls were sophomores in the district. A third girl was with them at the time and reported the accident.
Their names have not been released.
Four tracks had to be shut down after the accident and train line service was delayed.
Amtrak spokeswoman Tracy Connell says all tracks were reopened by 1 p.m. and service has returned to normal.