Rush-hour service on the 6 train was snarled Wednesday evening after a woman was struck by a train on the Upper East Side, FDNY officials said.

The woman was lying on the local tracks at the 86th St. and Lexington Ave. station when she was hit by the southbound train at around 5:40 p.m., officials said.

She was alive when she was transported to New York-Presbyterian Hospital but her condition is not known.

Cops were advising the throng of commuters to use the 59th Street station – but reopened the 86th St. station an hour later allowing straphangers to use the express 4 and 5 trains.