I stumbled across
This site recently, maintained by a Paul Strubeck (is he a poster on this site?) last updated a year or so ago - anyway that page starts off with images of what I thought was this siding (west of Commack Rd, across from Home Depot, south of the LIRR main) which slopes down westerly behind the PC Richards, then branches out into a few sidings (the westernmost ones covered with seemingly solidly packed truck trailers, according to Google Earth). However, the pictures on his site clearly show the branch disconnected from the switch. Hmm
Was this just a temporary situation (until the track was repaired), is he referring to a different branch (looks correct, though), is this ElDee spur a different branch? So, what's the deal?