My best guess on this is that it is for emergency car storage when floods threaten, like Sandy. I've read that NJT was eying the Delco lead for that. What I'm not sure of is if they are bascially just going to upgrade (and elelctrify) the existing track, or put down a second track on the real estate they are buying. My guess is just the one track, and if there are any customers (which is doubtful south of the Route 1 overpass), they'll just have to wait for the few days (?) cars are stored during a flood emergency.
Also, best I can tell is that the southern (timetable western) end of this segment, MP 36.4, is around the southern end of the old J&J plant, about where Costco is now. The line seems to go another mile before it turns away from Amtrak, but does not look active south MP 36.4, or even that far. Maybe some one else owns south of MP 36.4
My real question, though , is this just for car stoage, or does the real-estate figure into the 'North Brunswick loop" over the NEC that has been talked about for years.