NYPD: Man has leg severed after falling on train tracks, being struck by train in Park Slope

Police say a man is in critical condition after he fell on train tracks and was struck by a D line train in Park Slope Sunday.
Citizen App video displayed emergency vehicles on the scene when the incident happened around 11:50 p.m.
Investigators say it happened outside the Atlantic Avenue-Barclays Center station.
Officials say the 30-year-old victim's leg was severed.
He is currently at a hospital and is in critical condition.