A man died after he fell off the subway platform and touched the third rail at an Upper East Side station early Saturday, officials said.

The victim tumbled onto the tracks at 77th Street around 4:40 a.m. just as a northbound 4 train was pulling into the station.

The train operator was able to break in time, to no avail. When the motorman investigated, he saw the victim seizing next to the third rail, officials said.

EMS declared the man dead on scene. It remains unclear what led the man to fall.