PHILADELPHIA (CBS) – Eight months after the deadly Amtrak derailment in Philadelphia, there is a new theory about what might have caused the crash.

Investigators think the engineer may have been distracted by radio chatter from other train operators when the train jumped the tracks in Frankford.

Brandon Bostian has not spoken publicly since the crash last May that killed eight and injured more than 200 others.

The NTSB is expected to release new details about the crash next week.