It happened after 3:00 p.m. Monday on the tracks near the 900 block of Wagon Town Road in Valley Township.
The derailment sent two railcars plunging into the Brandywine Creek. A locomotive also jumped the tracks.
The accident startled neighbors like Michael McCoy.
"I was down working by my car," he said. "I heard the train coming up the tracks. It was going kind of fast. And then next thing you know I hear, 'Boom, boom, boom!' And then I saw all the fire trucks and ambulance."
No passengers were on the train.
Valley Township officials say it was transporting material for ArcerlorMittal, a steel manufacturing company in Coatesville.
The affected line is a branch off the Amtrak line that services the steel plant. Norfolk Sourthern maintains and operates it.
"There will be an investigation into what caused this," said Norfolk Southern's Dave Pidgeon. "I don't have anything I want to share about that. But certainly we are interested in how this happened and if there is anything we can do to prevent something like this in the future."
"Fortunately there were no chemicals on the train and no passengers, so no one was injured," said Westwood Fire Company Battalion Chief John Sly.
This is second mishap involving ArcerlorMittal during the past few months. On May 24th, a bucket containing molten steel exploded in the plant, sending three people to the hospital.
Norfolk Southern is now assessing the best way to get the derailed cars out of the Brandywine Creek.
"The bridge structure appears to be sound and safe, but it has sustained significant track damage," said Pidgeon.
The rail company says at this point neither the Federal Railroad Administration nor the NTSB is investigating.