A railroad accident deconstructionist details what goes into an inspection following the derailment in Pueblo County

PUEBLO COUNTY, Colo. (KRDO) - Coal and train cars were spread out all across Interstate 25 for days following Sunday's train derailment that left one man dead just north of Pueblo.

Investigators believe that a broken rail caused the derailment even though a Burlington Northern Santa Fe railroad team inspected that stretch of track that very same day of the incident.

"I strongly suspect that that inspection that they're referring to was one of the twice weekly tasks where you have a track inspector that runs a high rate vehicle, and they pass over the track and they… they visually examine the track as they pass over it," said Robert Halstead, a Railroad Accident Deconstructionist.

Halstead said he believes this type of inspection can only pick up the most egregious type of rail defects.

"Some of them are easy, some of them are visual, where you have a chunk of the head of the rail physically broken out. Others are, you know, on the order of millimeters aside. And that can be very difficult to visually identify," said Halstead.

Halstead believes the inspection that occurred the day of the incident is a prime example.

"The only thing that would have caught this is an ultrasonic inspection. And, you know, that's done typically once a year," said Halstead.

But the broken rail is just one part of the equation, the National Transportation Safety Board (NTSB) also tells us that a warning system designed to detect a broken rail failed preventing an alert.

NTSB is now investigating what caused the rail break and why the early warning system stopped working. They plan to see some initial findings as soon as a month from now, but a final NTSB report could take at least a year, according to our previous reporting.