The girl was struck by the Montclair Boonton Line train 1079 west of Abbot Road in Montville just before 5:50 p.m., an NJ Transit spokesperson told Daily Voice.
The train had departed the Hoboken terminal at 4:32 p.m and was scheduled to arrive at Hackettstown at 6:39 p.m, authorities said.
The girl was taken to Morristown Medical Center with serious injuries, authorities said.
The seven passengers onboard the train were uninjured, authorities said.
The Montclair Boonton Line was temporarily suspended between Lincoln Park and Denville but has since resumed.
The accident remains under investigation.
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