A team of investigators from the National Transportation Safety Board (NTSB) has begun investigating a train collision in Iowa that killed two workers Sunday morning.

The accident occurred t 7 a.m. CDT in McPherson, Iowa, when a Burlington Northern Santa Fe Railway coal train rammed into a BNF train hauling maintenance equipment belonging to the railroad. Both trains had two-person crews. The conductor and engineer on the coal train were killed. The crew on the other train was not injured.

According to the NTSB, two locomotives and multiple cars derailed as a result of the collision. Clean-up efforts continue on site.

The seven-member NTSB team which will attempt to determine the cause of the wreck will be headed up by Investigator-in-Charge Michael Flannigan.