CHICAGO (CBS) -- Federal authorities said Tuesday that a coal train derailment last July that killed a Glenview couple was likely the result of heat causing railroad tracks to buckle.
Burt and Zorine Lindner were driving on Shermer Road last Independence Day, just south of Willow Road, just as a Union Pacific freight train loaded with coal from Wyoming derailed as it was crossing a railroad bridge. The bridge collapsed, crushing the Lindner's car underneath.
Initially, because of the sheer size of the train wreckage, authorities did not know anyone had been injured in the collapse, until the Lindner's car was dug out the next day.
On Tuesday, the Federal Railroad Administration said it's likely that temperatures of 103 degrees on the day of the wreck heated the tracks, causing them to buckle at the site of the derailment, along the border between Glenview and Northbrook.
At least 28 cars – carrying an average of 75 to 85 tons of coal each – went of the track, piling up ina huge mound on top of the overpass, which collapsed onto the street below.
The Lindner's sons have sued Union Pacific, alleging negligence by the company.
Court documents in the case reveal an anomaly was noticed in the tracks that morning. A supervisor was even called, arrived but they contend failed to act.
"I'd like them to say what they did wrong," said Rob Lindner. "Fix it and make sure it doesn't happen to another family."
The railroad has said the bridge was not designed to hold the weight of the 28 fully loaded cars that ended up on the overpass after the derailment.
Union Pacific has said a new bridge will be in place by the end of the year.
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