Federal investigators blame triple-digit heat for last summer's deadly freight train derailment in Chicago's northwest suburbs.
The Federal Railroad Administration said in a report it is likely that temperatures of 103 degrees heated the track and caused it to buckle a few feet before the bridge near the suburb of Northbrook.
The fully loaded coal train weighed more than 19,000 tons when it derailed, sending 32 freight cars off the track. Nearly all of them piled up in a spectacular mound directly on top of the overpass, causing it to collapse.
Burton Lindner, 69 and wife Zorine Lindner, 70, were discovered inside their car beneath debris. The couple lived a block away the site of the derailment, which spilled thousands of tons of coal from the train.
The couples' sons, Matt and Rob Lindner, filed a wrongful death lawsuit against Union Pacific and they said earlier this month the suit is caught up in the appeals process.
"The Federal Railroad Association agency decided, oh, they wanted to handle this one. They jumped right in. A year later they've done no investigation that we know of, there's no report that they put out. We don't know what happened," Rob Lindner said.
Internal, handwritten notes supplied by Union Pacific further clarify what the company said in the days following the accident: that an employee had reported an anomaly with the track in the hours before the train derailed that day.
A safety advisory notice from the Federal Railroad Administration released weeks after the derailment pointed to rail buckling, commonly referred to as "sun kinks," as the preliminary cause of the derailment.
Shermer Road has since been filed with gravel and new railroad ties have been laid to accommodate the nearly one dozen freight trains that pass through the area each day.