By Frank McGurty
NEW YORK, May 20 (Reuters) - Federal investigators are analyzing the cell phone records of the engineer in last week's deadly Amtrak derailment to determine if he was making calls or texting when he was operating the train, officials said on Wednesday.
Investigators are aware that engineer Brandon Bostian made calls and texts on the day of the May 12 crash in Philadelphia that killed eight and injured more than 200, but do not yet know if any of the activity was during the time he was operating the train, the National Transportation Safety Board said.
The process is "detailed and lengthy," it said in a statement.
Amtrak engineers are required to turn off their phones when behind the controls, officials have said.
The train, which was barreling north at double the 50-mile-per-hour (80-kph) speed limit when it entered a sharp curve and derailed, was en route to New York from Washington with 243 people on board.
The NTSB also said investigators had interviewed the engineer of a Southeastern Pennsylvania Transit Authority commuter train that had stopped on the tracks after its windshield was hit by an unidentified object.
Shortly before the Amtrak train derailed, the SEPTA operator said Bostian radioed him to say the Amtrak train was passing. The SEPTA engineer said he noticed nothing unusual about the Amtrak train as it went by on an adjacent track.
The NTSB said on Friday an assistant conductor on the Amtrak train told investigators she overheard a conversation between Bostian and the SEPTA engineer. She said she thought she heard them discuss one or both of the trains being hit by objects.
While SEPTA has confirmed its train was hit by a projectile, there has been no confirmation on what may have caused circular damage found on the windshield of the Amtrak locomotive.
The FBI has found no evidence the damage was caused by a firearm.
Bostian, 32, who suffered a concussion, told investigators he had no memory of what occurred just before the crash.
Before Friday's disclosure about possible projectiles, the probe was focusing on why the train accelerated to 106 mph (170 kph) from 70 (112 kph) in the minute before it derailed.
The NTSB has not ruled out mechanical issues, human error or a deliberate act by the engineer, among other factors.
(Reporting by Frank McGurty; Editing by Peter Cooney)