Unlike other "abandoned" train stations in the New York City area, the infamous Track 61 is supposedly still in use as a secret escape train for presidents visiting the city.
Built along with the rest of Grand Central Terminal, Track 61 was never properly abandoned as it was actually constructed to be a powerhouse and storage area for unused New York Central Railroad cars, not a passenger station. (Contrary to some belief Track 61 is not part of the NYC Subway but rather part of the New York Central Railroad now Metro-North.)
The station is not much to look at, what with all the untended grime and dirt, but there is still an antique train car permanently parked in the hidden powerhouse. However the dingy, industrial stretch of track has managed to gain a fair amount of fame as the private transport stop for US presidents.
The earliest reported use of the track was during the tenure of Franklin D. Roosevelt who supposedly had his car transported to the station which was then lifted right into the Waldorf's garage. Roosevelt is also rumored to have entered and exited via the station in order to hide his worsening case of Polio. Track 61 likely hid the comings and goings of a number of POTUSes over the years and was confirmed to be prepped for a quick getaway route for George Bush Junior while he took meetings at the Waldorf.
Everyone from military generals to celebrities have been said to use Track 61 for all number of clandestine movements, but given the amount of secrecy involved, all are hard to confirm. However the unmarked brass door at the Waldorf's street level which leads to the station is proof that someone important is still using the track.