At least it ain't that. That would be the Erie RR's Northern Branch, which runs parallel through Tenafly. That line was two-track, and ran onto the Piermont Branch in Sparkill NY.
These pix are of the current CSX "River Subdivision"; note the NY Central operating. And frankly, NJT's current spur to the Meadowlands was supposed to be connected to the River Sub so that West Shore commuter trains could run again (the intent being to run them through Secaucus, for the transfer; but of course we now have the upcoming magical ALP-45DP "dual-power" thingies, so who knows if this might be resurrected, if they actually work that is).
In the distance is the concrete overpass of Route 4 .I drove over daily from 1970-1976 going to school.By then, it was only 2 tracks and it was Penn Central.There were long freights every day going each way.
Another area they ripped out two tracks was the old Erie running through Mahwah NJ.Used to be four tracks there also.