PUEBLO, Colo. — A railroad line was inspected hours before a train derailed and killed one person, a spokesperson for the train company, BNSF, told 9NEWS.
The train derailed because of a broken rail, according to a preliminary investigation by the National Transportation Safety Board (NTSB). Despite the inspection earlier that day, the train derailed at a bridge over Interstate 25, killing Lafollette Henderson.
"It’s possible to have inspected and missed it for a variety of technical reasons and I am sure that NTSB and BNSF are right now looking at all those possibilities," said Dr. Allan Zarembski, the director of the Railway Engineering and Safety Program at the University of Delaware.
Zarembski says it's also possible— but not probable— that something happened after the inspection, causing the rail to break.
"It is possible that some event triggered a very large dynamic force, which if sufficiently large, and if you have a very small defect in the rail, can possibly break the rail," he said.
If something did happen, Colorado Governor Jared Polis repeated NTSB's preliminary finding that it was not related to the bridge.
"We have no reason to believe the bridge played any role in this accident," said. Governor Jared Polis.
There have been 4,412 train derailments between January 2014 and July 2023, according to the Federal Railroad Administration. 167— or 3.8%— of the derailments were caused by a broken rail.
"Whatever we find the cause to be, it's going to be a low probability occurrence event," Zaremsbki said.
BNSF's spokesperson did not explain what type of inspection they did Oct. 15, but the company says the line was inspected in multiple ways and multiple times within the last three months.
Here's an overview of the types of tests BNSF did:
RAIL DETECTION TESTING
This is a type of testing using ultrasonic waves.
"By looking at the signature of the pulse they can identify the type of defect, size of defect, where it's located, what's working, and ultrasonic detention is about 99.99% effective," Zarembski said.
ADANCED TRACK INFRASTRUCUTRE TESTING
"That's a very broad term that encompasses a lot of different testing," Zarembski said.
VISUAL INSPECTIONS
"Track has to be walked, physically walked, or inspected at a very low speed from a slow moving vehicle once or twice a week depending on the criteria," Zarembski said.
Governor Polis says he expects all of the Interstate 25 lanes to be open by Thursday evening.