A Philadelphia judge has ruled that there is "probable cause" to charge Amtrak engineer Brandon Bostian in the deadly 2015 train derailment.

The Amtrak train bound for New York City crashed in Philadelphia, killing eight people and injuring hundreds.

The move comes after a reversal of the district attorney's Tuesday decision not to file charges.

"The district attorney's office has refused, steadfastly, until this order, to even prosecute this man," says Attorney Thomas R. Kline, who is representing the families of those killed. 

The NTSB investigation found that Bostian was distracted by radio conversations about other trains being hit with projectiles. The train's data recorder showed it was traveling at 106 mph around a sharp curve with a speed limit of 50.

The district attorney says there was no evidence Bostian acted with criminal "intent" or criminal "knowledge." In response, attorneys filed a private complaint on behalf of the father of one of the victims.

The judge ruled that charges of involuntary manslaughter and reckless endangerment can be brought against Bostian, both as misdemeanors. The judge also ordered the filing of two private criminal complaints against him.

The district attorney has referred prosecution of the case to the Pennsylvania attorney general to avoid any apparent conflict of interest.

Bostian did not return calls for comment.