The Monona County Sherriff’s Department told the Associated Press that a Union Pacific train loaded with coal jumped the track at about 5.45pm in Harrison County.

Nine cars of the train derailed, and officials said no hazardous materials were involved in the incident.

An investigation has commenced to determine cause. UP officials told the AP Tuesday night that a brake problem forced the train to stop, which then resulted in the derailment.

The incident follows a trio of other similar events across the US, including a Burlington Northern Santa Fe train with 121 loaded cars and three locomotives that lost 18 cars in a derailment earlier this month near Brainerd, North Dakota.

The train was headed for Superior, Wisconsin, and the spill near the Brainerd Lakes Regional Airport blocked a main track.

A BNSF spokesperson told the AP just after the derailment that it was seeking the cause.

The same weekend as the North Dakota event, a derailment in western Nebraska resulted in a coal train losing dozens of cars near Lake McConaughy, between Sand Creek and Martin Bay.

Investigators are looking into the cause of this spill as well.

Also earlier this month, nearly 30 Indian Railroad train cars left the tracks near Bloomington, Indiana, the second derailment in the area in a five-day span.

Indiana Monroe County chief deputy Mike Pershing told the news service that the train’s engineer said heat may have played a role in second Indiana incident.