A defense lawyer argued Tuesday that any mistakes made by Brandon Bostian do not amount to a crime, and a city judge agreed.
The Philadelphia Inquirer quotes Judge Barbara McDermott as saying, "the law recognizes we're all human."
Two judges have now dismissed charges against Bostian in the 2015 derailment that left eight people dead and about 200 injured. The state Attorney General's Office says it will appeal the latest ruling.
National Transportation Safety Board investigators concluded Bostian lost his bearings while distracted by radio chatter about a nearby train that was struck by a rock.
Investigators say the train rounded a curve at more than twice the 50 mph (80 kph) speed limit.