Track in Riverdale section of the Bronx

Had noticed this track while traveling into the city several months ago, and then remembered it when I saw this picture. Was wondering what the history of the track on the far left is. When was it in service. Did it serve both passenger and freight and if it's out of service, when did it go out. Any info would be great as I've been wondering about it.
http://www.railpictures.net/photo/638127/" onclick="window.open(this.href);return false;

That's an active freight track for CSX extending from just north of the Empire Connection to just south of Yonkers station. Used to serve a thicket of freight customers around Ludlow, but most of those are defunct so now it's just a way for freights to stay out of the way of passenger trains. In the NY Central days electric territory was contiguous 5-track all the way from Spuyten Duyvil Jct. to the vicinity of Hastings-on-Hudson; the former Track 5 berth is readily visible along the river, and it's dotted by a few sidings north of where today's freight lead ends.