Burt and Zorine Lindner, both 70, were driving in suburban Chicago last year, between the northern neighborhoods of Glenview and Northbrook, when a loaded Union Pacific coal train lost 32 of its 138 cars.

Agency officials said the temperature on that day, 103F, likely led to the derailment that sent the railway bridge crashing down last July 4.

UP estimated the train weighed more than 19,000 tons at the time of the incident.

The family of the victims sued the railroad, claiming negligence.

According to the Associated Press, court documents reveal an anomaly in the tracks the morning of the incident that was not acted upon, despite a supervisor being called in to review it.

“I’d like them to say what they did was wrong,” son Rob Lindner told the news service.

“Fix it and make sure it doesn’t happen to another family.”

UP also said, after the derailment, that the bridge was not designed to hold the weight of the cars that left the tracks.

It has since estimated that a new bridge would be ready for use by the end of the year.