![Amtrak Crash Amtrak Crash](https://api.time.com/wp-content/uploads/2015/06/amtrak-crash.jpg?quality=85&w=2400)
The National Transportation Safety Board’s investigation of last month’s deadly Amtrak crash outside Philadelphia is zeroing in on the engineer’s cell phone records after establishing that there were no mechanical problems that contributed to the accident.
According to a preliminary report released Tuesday, the NTSB has established that there were “no anomalies” in the train’s brake system, signals or track structure. Investigators have obtained engineer Brandon Bostian’s cell phone records and have established that calls and texts were made that day, but they’re still working to figure out whether he was on his phone as he was driving the train. Bostian suffered a head injury in the crash, and his lawyer has said he has no memory of what happened.
The NTSB also found damage to the train’s windshield, but couldn’t determine whether this came from rocks that were thrown at the train or from the crash itself. They found no evidence that the damage was caused by gunshots.
See Photos of the Amtrak Train Crash in Philadelphia
![Amtrak Crash Emergency personnel work the scene of the Amtrak train wreck on May 12, 2015 in Philadelphia.](https://api.time.com/wp-content/uploads/2015/05/amtrak-train-crash-07.jpg?quality=75&w=2400)
![Amtrak Crash Emergency personnel work the scene of the Amtrak train wreck on May 12, 2015 in Philadelphia.](https://api.time.com/wp-content/uploads/2015/05/amtrak-train-crash-03.jpg?quality=75&w=2400)
![APTOPIX Amtrak Crash Emergency personnel help a passenger at the scene of the Amtrak train wreck on May 12, 2015 in Philadelphia.](https://api.time.com/wp-content/uploads/2015/05/amtrak-train-crash-06.jpg?quality=75&w=2400)
![Rescue workers climb into the wreckage of a derailed Amtrak train to search for victims in Philadelphia Rescue workers climb into the wreckage of a derailed Amtrak train to search for victims in Philadelphia on May 12, 2015.](https://api.time.com/wp-content/uploads/2015/05/amtrak-crash-philadelphia.jpg?quality=75&w=2400)
![Amtrak Crash Emergency personnel work the scene of a train wreck on May 12, 2015, in Philadelphia.](https://api.time.com/wp-content/uploads/2015/05/amtrak-train-crash-08.jpg?quality=75&w=2400)
![Amtrak Crash Emergency personnel work the scene of the Amtrak train wreck on May 12, 2015 in Philadelphia.](https://api.time.com/wp-content/uploads/2015/05/amtrak-train-crash-05.jpg?quality=75&w=2400)
![Amtrak Crash A crime scene investigator looks inside a train car after a train wreck on May 12, 2015, in Philadelphia.](https://api.time.com/wp-content/uploads/2015/05/amtrak-train-crash-01.jpg?quality=75&w=2400)
![Amtrak Train Derailment Causes Mass Injuries In Philadelphia A police officer takes a seat near the wreckage of an Amtrak passenger train which derailed in Philadelphia on May 12, 2015.](https://api.time.com/wp-content/uploads/2015/05/amtrak-train-crash-philadelphia-2.jpg?quality=75&w=2400)
![Officials survey the site of a derailed Amtrak train in Philadelphia, Pennsylvania Officials survey the site of a derailed Amtrak train in Philadelphia on May 13, 2015.](https://api.time.com/wp-content/uploads/2015/05/amtrak-train-crash-philadelphia.jpg?quality=75&w=2400)
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Write to Charlotte Alter at charlotte.alter@time.com