PHILADELPHIA — An unusual, 11th-hour attempt to put an Amtrak engineer behind bars for a deadly 2015 derailment in Philadelphia unraveled Tuesday as a judge dismissed the case without trial because he found the evidence pointed to an accident, not negligence.

Judge Thomas Gehret’s rationale echoed the thinking of city prosecutors, whose decision in May not to charge engineer Brandon Bostian led a victim’s family to seek charges on its own as a statute of limitations loomed.

Bostian, 34, hugged his lawyer as Gehret made his ruling at the end of a four-hour preliminary hearing that saw seven witnesses reliving aspects of the May 12, 2015 crash.

He’d faced charges including involuntary manslaughter and reckless endangerment.

Bostian’s Washington-to-New York train rounded a sharp curve at more than twice the 50 mph speed limit and hurdled off the tracks in a violent derailment that crumpled cars and catapulted passengers into the woods.

Eight people died and about 200 were hurt.

Bostian’s lawyer, Brian McMonagle, said his speeding was a momentary lapse from a safety-conscious engineer who had lost his bearings after being distracted by an incident with a nearby train.

“Obviously this is a terrible, terrible tragedy, but today there was justice,” McMonagle said after the hearing.

A National Transportation Safety Board investigation completed last year found no evidence that Bostian was impaired or using a cell phone.