The person, whose identity was not immediately released, was struck by a Manhattan-bound train about 9 a.m., an FDNY spokesman said.
The person was not immediately taken to a hospital and crews were still on scene about 30 minutes later, he said.
F train service was disrupted in both directions during the morning commute, according to the MTA website.
Shuttle trains were running in both directions between Stillwell Avenue and Kings Highway, the MTA said. There were no trains running between Kings Highway and Church Avenue.
Manhattan-bound trains were bypassing Avenue U, the MTA said.
Commuters were advised to expect additional travel time.
The incident comes hours after a man was electrocuted while walking over subway tracks in Williamsburg.