One of my favorite radio shows is "America Coast to Coast with George Nory" and there is very interesting stuff there dealing with UFO's. Many people worldwide have seen UFO's, sometimes seen as colored lights in the sky. It would be helpful if the beings in charge of these UFO's would adopt the system below to help us earthlings know their destinations. Or perhaps, since we can always use more transportation help here in New York, we can recruit the UFO's to provide transit services. So therefore, if you see two colored lights in the sky over the Bronx which are yellow and white, it is a "D" bound UFO headed towards Brighton Beach.while you see one light that is white and one is green over Downtown Brooklyn, it is a GG UFO bound for Smith-9th Street.
Incidentally, the IRT subway and the elevated lines such as the 3rd Avenue El had also their own system of marker lights.
Subway FAQ: Subway Train Marker Lights
|Line||Destination||Cab Marker||Opposite Marker|