The preliminary investigation points to speed as a contributing factor of the crash. The track where the derailment occurred has a six-degree curve and a speed limit of 30 mph. NTSB says the train speed at the time of the accident was 82 mph.
NTSB's inspection and testing of the signal system, train brakes, other mechanical equipment, as well as the track infrastructure did not identify any anomalies.
The derailment resulted in four deaths, 59 injuries and a damage estimate of $9 million. NTSB will continue its investigation and notes that the information in the preliminary report will be supplemented or corrected during the course of the investigation.