Yeah, I've broken down twice in the past few years and bought frozen White Castles, and they made me sick both times. No mas. It's the real thing or nothing.
White Castles were 5 cents each back in the '60s; they're about 80 cents now. I was in high school in the late '60s, and we would go through bags and bags of the things. That's when they started offering cheeseburgers as an option, and later fish sandwiches, but I've always been an originalist when it comes to White Castles: just a burger on a steamed bun, onion and pickles.
Krystals in the mid-South are very close, and they have been around almost as long.
They are actually wonderful, and highly addictive. I can see how that photo I posted might give you the "assembly line" impression, though. This is probably a better one.
...though I disapprove of the cheese, of course.
I can't express how incredibly hungry for White Castles these pictures make me.