Amtrak's Northeast Corridor between Philadelphia and New York and SEPTA's Trenton Regional Rail line are scheduled to resume service Monday morning, even as the investigation into the fatal train derailment that took place on those tracks last week continues.

The U.S. Department of Transportation's Federal Railroad Administration has ordered Amtrak to install positive train control, a technology that forces trains to slow and adjust their speeds to match speed limits, on the tracks where Amtrak 188 derailed, as well as along the entire Northeast Corridor.

Meanwhile, reports say that the FBI was investigating a "grapefruit"-sized crack on the windshield as a possible contributing factor to the derailment that killed eight and injured 200 people aboard the train.

The train's engineer says he has no recollection of the crash.