Just before Tuesday's deadly Amtrak derailment, a SEPTA commuter train in the same corridor was crippled by a projectile sent through the engineer's window.
SEPTA officials said their investigation was continuing, but that there was no immediate indication the two incidents were related.
At about 9:25 p.m. Tuesday, SEPTA's northbound Train 769, en route to Trenton on tracks on the Northeast Corridor beside the Amtrak rails, was struck by "an unknown projectile" that broke the engineer's window, SEPTA spokeswoman Jerri Williams said.
No injuries were reported and the train was held at the North Philadelphia station. The 80 passengers were transferred to buses.
About three minutes later and four miles away, near Frankford Junction, Amtrak's northbound Train 188 derailed on the Northeast Corridor tracks, killing at least six and injuring more than 200.
The cause of the derailment is under investigation by the National Transportation Safety Board and the Federal Railroad Administration.
"There is no indication at this time that the two incidents are related in any way," Williams said early today.
Event recording device recovered
Meanwhile, Philadelphia Mayor Michael Nutter said a "black box" recording device has been recovered and sent to an Amtrak analysis center in Delaware. The device includes a forward-facing camera.
Robert Sumwalt with the National Transportation Safety Board said investigators are looking at factors including track signals, the train’s operation and the conductor’s actions.
First Published: May 13, 2015, 2:07 p.m.
Updated: May 14, 2015, 3:35 a.m.