A slide from my collection. The Royal Diner, February 1969. Slide is captioned Newark, NJ, but the diner is located at 647 Garden St, Elizabeth, NJ John Baeder has done a couple of paintings of this diner.
It still stands, horribly remodeled with a second story addition.
Diner Hunter 
link to the paintings?
Gone now, I presume? Are you familiar with WhatWasThere.com? This would make a good contribution.
It’s still there, but you’d hardly recognize it. Badly remodeled with an added second story.
http://akronartmuseum.org/collection/Obj2459?sid=300&x=163185
I was friends in grammar school with the owner’s younger daughter. We used to roller-skate inside when it was closed. Had a great jukebox.