A CSX derailment was blamed on maintenance.

The Federal Railroad Administration said the cause of the accident last July 8 at Miamisburg, Ohio, was a shifting of the track caused by high temperatures, a phenomenon known as a “sun kink.” The FRA said: “We have also concluded that the probability of a sun kink’s occurrence was enhanced by the carrier’s failure to follow . . . track maintenance practices which required placing a slow order on this track segment after resurfacing.” The derailment caused a phosphorus fire that forced as many as 30,000 people to flee their homes in what the FRA said was the largest evacuation in U.S. rail history.