Earlier this week, Philadelphia District Attorney Seth Williams announced that he would not press charges against Bostian because there was no evidence of criminal intent or responsibility.
The charges against Bostian, 34, of Forest Hills, New York, include Causing or Risking Catastrophe, Involuntary Manslaughter, Recklessly and Endangering Another Person. The federal organization focused on a radio conversation between Bostian, a dispatcher and a SEPTA Regional Rail engineer who claimed rocks were being thrown at his vehicle around Frankford Junction, where Bostian's train was traveling. However, federal safety investigators concluded that nothing struck the train prior to it crashing.
When NTSB investigators interviewed him, the discussion of trains being hit by a projectile was one of the few details the engineer remembered clearly.
"We've received the referral from the Philadelphia District Attorney's Office and are carefully reviewing this important matter", Joe Grace, a spokesman for the state attorney general's office, said on Friday.More news: Iraq, Algeria support extension of oil production cuts
Prosecutors on Wednesday said they can't prove engineer Brandon Bostian acted with "conscious disregard" when he accelerated the train to 106 miles per hour on a 50 miles per hour curve in Philadelphia.
The New York-bound Amtrak 188 entered the curve going more than double the speed limit, flinging multiple train cars free from the tracks and tearing up some of the railway's I-beams.
However, the Philadelphia's district attorney's office determined that the evidence did not rise to the necessary level needed to charge the engineer or anyone else with a crime. The other people killed included Justin Zemser, a Naval Academy midshipman; Jim Gaines, an Associated Press software architect; and Derrick Griffith, a college dean.
This portion of track was not equipped with positive train control or even a less technologically-advanced piece of equipment that could have prevented the train from traveling at such a speed.More news: US Justice Department orders tougher criminal punishments
Bostian has a personal injury lawsuit pending against Amtrak. The NTSB has said had that equipment been installed the accident would not have happened. Two children died in the ensuing crash.
Two trains operating on the same route were struck by flying rocks that night - the SEPTA regional rail train and an Amtrak Acela heading for Philadelphia's 30th Street Station.
The engineer responsible for a deadly 2015 Amtrak train derailment in Philadelphia has been charged with involuntary manslaughter.
On Wednesday, the family of 39-year-old Rachel Jacobs, who was killed in the crash, filled out a private citizen criminal complaint, which the DA's office again declined. The Inquirer also reported that while it's uncommon for a judge to overrule the DA's office, it isn't unprecedented.More news: Wall hits late 3, forces Game 7
"This is a moment of justice".