Officials from the National Transportation Safety Board (NTSB) are currently gathering data to figure out what caused the trains to crash. The Safety Board's preliminary findings show that the train signals were working properly at the time of the crash. It is unclear why one of the trains failed to pull off onto a side track prior to the crash, leading Federal Railroad Administration official to speculate that human error might have caused the head-on collision. NTSB officials will also be looking at phone records of both train crews to make certain that no one was distracted by mobile devices.
According to the Associated Press, the NTSB will likely release a preliminary report in a couple of weeks, and it may take upwards of a year for them to finish their final report.