The victim touched the highly-charged third rail in the trackbed of the northbound express trains and was electrocuted about 6:55 a.m., police and FDNY spokesmen said.
Police said the victim, believed to be in his 30s, committed suicide and do not suspect a crime was committed.
An MTA official in the station said witnesses told him that the victim's head and hand came in contact with the charged rail. Some straphangers rushed to the ledge to help him, he said, but backed off when they saw "sparks."
Meanwhile, the MTA said nearly every subway line will be affected this weekend because of maintenance work.