The Amtrak engineer who controlled the train that fatally wrecked in Philadelphia two years ago has been arraigned and released on charges including involuntary manslaughter.

Pennsylvania Attorney General Josh Shapiro's Office last week announced the charges, which came as a shock to many legal observers.

Philadelphia's District Attorney's Office and federal authorities declined to charge Bostian, citing insufficient evidence.

But then a Philadelphia judge ordered city prosecutors to charge and arrest Bostian following a private criminal complaint that was submitted by the husband of one of the crash victims. 

The DA's Office referred it to Shapiro's office and they ultimately approved the prosecution. 

In order to convict someone of criminal recklessness in Pennsylvania, there has to be proof that the person conscious ignored the risk to human life.

Being accused on that has been difficult for Bostian, according to his lawyer.

"Well, can you imagine being charged and told you murdered eight people and injured 200-plus more, and caused a billion dollars worth of problems, and everyone's blaming you?" Robert Goggin, Bostian's lawyer, said. "You can imagine the guilty that's placed around his neck and the horror he has for all the victims and their families."

He said Amtrak is ultimately to blame for the fatal derailment in May 2015 for not having installed positive train control, which is an automatic breaking system activated along the Northeast Corridor in the wake of the wreck.

Goggin said he's hopeful the AG's Office will withdraw the charges after examining the facts more carefully.

"The evidence in the case has not changed," Goggin said. 

The National Transportation Safety Board concluded that Bostian lost "situational awareness" in the moments leading up to the fatal derailment. He was distracted by radio reports that a nearby commuter train was getting struck by rocks, causing Bostian to momentarily forget his position along the route. He accelerated to 106 mph around a tight bend in the tracks. That was double the posted speed limit. 

Bostian has been released on a bond as he awaits his next court date in June.