NILES (WKZO) -- Officials say a reversed switch is the cause of Sunday's derailment of a Pontiac bound Amtrak train in southwestern Michigan.

A report from the National Transportation Safety Board found the train was given a green signal to travel at maximum speed near Niles, but a switch just past the signal was reversed, taking the train off the main track and into a rail yard, where it derailed.

Nearly 180 people were on the train heading from Chicago to Pontiac at the time of the incident.  Seven passengers and two crew members were injured and all were treated and released from area hospitals.