I love stuff like this. Another really cool site Forgotten NY (linked below too) has lots of posts like this for history people.
Over the weekend we had a chance to visit the long-abandoned Waldorf-Astoria train platform, which allowed VIPs to enter the hotel in a more private manner—most famously it was used by Franklin D. Roosevelt, possibly to hide the fact that he was in a wheelchair suffering from polio. The mysterious track, known as Track 61, still houses the train car and private elevator, which were both large enough for FDR's armor-plated Pierce Arrow car. Legend has it that the car would drive off the train, onto the platform and straight into the elevator, which would lead to the hotel's garage. Trainjotting has some more history regarding the platform, known as Track 61, and notes that the quest for it "has become a holy grail for many urban explorers."
Source -> http://gothamist.com/2011/11/07/photos.php#photo-1
Related link -> http://forgotten-ny.com/