(The following article by Brad Rollins was posted on the San Marcos Daily Record website on March 1.)
SAN MARCOS, Texas — A Union Pacific Railroad official says the company is stumped by initial results of an internal investigation that found no apparent cause for a Feb. 11 freight train derailment in a San Marcos neighborhood.
An unspecified “combination of train and track dynamics” caused a box car loaded with scrap paper to lift off the rails when the train passed through an S-curve behind San Marcos City Hall, spokesman Mark Davis said. Seven cars, five of them containing sulfuric acid and xylene, overturned more than two miles further down the track.
Calling the circumstances “highly unusual,” Davis said investigators found no problems in any of three areas that typically lead to train derailments: human error, tracks and mechanical systems. Davis said measurements of track and rail car width met Federal Railroad Administration and company regulations. Additionally, no defects such as cracks or gouges were found in the rails, he said.
The spokesperson said he didn’t know of any other situations in which a train derailed for no apparant reason.
“That’s why its taken so long to find a cause,” he said. “They kept going back and checking everything and couldn’t find any defects.”
Spurred by the mysterious derailment, railroad engineers will use computer simulation and modeling to “try to find the relationship between track geometry and different kind of rail cars.”
“There’s a lot more that we need to know,” Davis said.
A written report will eventually be released through the Federal Railroad Administration, he said, but is not immediately available. The federal regulatory agency delegates investigatory authority to rail companies.
The derailment heightened local concerns about heavy freight traffic that traverses town on a daily bases. As many as two-thirds of the 25-35 trains that pass through each day carry hazardous material.
Mayor Susan Narvaiz said she, City Manager Dan O’Leary and council members John Thomaides and Gaylord Bose would press the issue in meetings with legislators and, hopefully, rail road administration official while in Washington next month for a conference of cities.
She is pressing a long-delayed plan to divert most through freight traffic to an alternative eastern route.
“We’re going to do whatever we can to expedite moving rail traffic out of town,” the mayor said.
Narvaiz has also called on Union Pacific to release maintenance records and inspection logs for tracks within the city limits. Davis said his company would probably comply if formally asked.
“We inspect the track a minimum of three times a week,” he said. “And inspect it visually probably every day.”
In addition, the rail road uses high-tech laser and ultrasound testing equipment at least once a year. Such a test was performed, and found no defects, two days before this month’s derailment.
O’Leary has said the same accident could have easily been “catastrophic” if the five hazardous material tanks overturned had been full instead of mostly empty. Each of the four 30,000 gallon sulfuric acid cars contained about 120 gallons. The car carrying xylene, a cleaning solvent, had about 280 gallons.
“If they had been full, instead of empty, we would be talking about a different situation,” O’Leary said earlier this month.
Six derailments or other accidents killed four people in San Antonio last year. Investigations there found causes ranging from fatigued train workers who ignored track signals to a segment of cars that came disconnected from the rest of a train for unknown reasons.