According to reports, 12 cars on the 129-car Norfolk Southern train went off the rails and four of them were full of coal.

Roads have been closed to allow authorities to clean up the mess.

Williamsport’s The Sun-Gazette quotes fire chief James Pfleegor saying the train was heading from Altoona to PPL Corporation’s Strawberry Ridge power plant.

He said four of the cars were upset and at least two were destroyed, with the undersides of some cars torn off during the derailment.

According to the paper, Pfleegor said special equipment was brought to the scene to help with the clean-up, which could take several days.

WTAG News reports that fire department officials said a mechanical issue caused the cars to derail.