I finally made it to...

...Johnnie's Beef in Elmwood Park today. The line wasn't too long, and the place across the street let me use their bathroom. Good thing, too, because Johnnie's doesn't have restrooms (as far as I could tell). Heck, they don't even have indoor seating, just a counter where you can stand and eat your beef sandwich.

I had mine with sweet peppers, a little wet. It was delicious.