Freight train de-rails with one car leaving tracks.

Investigators are probing what caused a train derailment in Chester County Wednesday morning.

The derailment happened at about 10 a.m. in the 1000 block of South 1st Avenue in Coatesville.

A train was pulling three flat bed cars when the back car became disengaged and came off the tracks. It was not immediately known what the flat cars were pulling.

There were no reports of any injuries.

The derailment remains under investigation.