Train of the Dead?

While waiting forever for a train the other day on the way to work, I saw a strange occurrence. A W train, which does not EVER stop in Brooklyn, went through my station, stopped for a while, and left. The doors never opened, and every window was blacked out. Clearly, the next stop on the this ghost train was Purgatory. I didn't get a chance to snap a pic (mostly out of fear for my soul), but it looked something like this:



Spooky, no?