More than wanting to substantiate his own existence, however, he was eager to marshal his considerable evidence that the 76th Street station exists and to add it finally to the list of others once thought to be ghosts and now rediscovered, such as parts of the storied old Polo Grounds shuttle.

Among what Mr. Krokowski calls his incontrovertible proofs:

* On the electric light board in the control room at Euclid Avenue showing the locations of trains, there is a part -- now black-taped over -- that says ''76th Street.'' (Joe Raskin, a transit official and part-time subway historian, says that this description of the board is correct, but adds that he can find no documentation that the station was ever actually built.)

*At a subway yard near 76th Street, there are remnants of old tracks that head northeast and then stop near a cinder-block wall. Mr. Krokowsi admitted that recently, during a fit of obsessiveness, he put on a safety vest, went into the yard with a shovel and tried to dig under the wall. He found a piece of a subway track tie, suggesting that tracks continued past the wall and into a sealed-up tunnel. But he had to abandon his illicit spelunking when part of his hole caved in.

*A fellow retired police officer told Mr. Krokowski that sometime in the 1960's, the cinder-block wall had a door and that he walked through it to the station, which was completed except for turnstiles and token booths. (The man did not respond to a message left yesterday at his home.)

*Several other transit employees also told Mr. Krokowski through the years that they had seen the station. All of them are unfortunately -- conveniently? -- deceased now.

Mr. Krokowski's fellow subway buffs are a skeptical lot, however, the kind of aficionados who can argue passionately for days about things with esoteric names like homeballs and trailing points. They say he damages his credibility by insisting that there is yet another abandoned station on the R line in downtown Brooklyn and that the engineer who designed it shot himself when he discovered a horrible error in his plans that caused the station to be shuttered.

''Dontcha know that engineers who screw up ALWAYS commit suicide?'' one skeptic, David Pirmann, commented sarcastically on the Web site. ''Seriously, that part reeked of urban legend to me; it casts a bad light on the rest of the story.''