Tracks at Riverdale (freight lead)

I have been railfanning at Riverdale and Yonkers for quite some time now. I prefer Riverdale though because express trains and Amtrak just blow right by. By me spending more time here I have studied the station a lot and was there when they were fixing it. There is something about the tracks though that keep me thinking. In between the river and the New York bound platform there is a track that is just well, "dead". What I mean is there is no trains being used on this track. They look well maintained but going north lead to no where but tall bushes. Going south they continue to go as far as I can see from the station. In the past 12 years I have only seen two trains on these tracks, both times non-revenue equipment. When was the last time these tracks were used for revenue service, if it saw any and for what purpose were they used for? Here is something random, a couple years back I was staring the tracks down for about two minutes and I heard noise and turned around and to my surprise it was a train of M2's heading towards GCT, small world eh?

the track behind station is CSX lead from CP12 to Sugarhouse in yonkers.
the track is one of only ones long enough to put a CSX train in clear incase of trouble.

If you go to the Ludlow station, you will see that there are two tracks coming off the lead; one to Tyco Plastics (They take delivery of raw materials by train.) and a second to the building that used to house Tyco, but now houses Hudson Scenic Studios. Hudson does not take delivery by rail. About two years ago they paved over the track area to provide more employee parking, but left the tracks in place.

Regarding the trackage north of DV, in NYC days we had Tks. 5 & 6 which served as freight mains between DV and the interlocking at Mt. St. Vincent where they converged with the other 4 main tracks.

This allowed the freights to access or clear the mains at reasonable rates of speed and not contribute to the choke point at Spuyten Duyvil (DV).

Track 6 continued as a non-signalled local service track to Glenwood interlocking (GD). In later NYC years, Tk. 6 was extended about a half-mile north of GD to allow freights to clear in without tying up the GD interlocking which was one of the points where some commuter runs originated / terminated and which had only one way complete cross-overs.

Hope this helps.