Could it be The Pit in Hickory Hills?
http://www.thepitribhouse.com/
Hickory Hills is more SW than Elmwood Park, has been around for years like Russell's, and I know they have nice onion rings. The ribs are real nice too, and they have an unusual BBQ Beef- basically the same beef as used in Italian beef, but drenched in BBQ sauce.
Russell's has very nice ribs as well, with a sweet and unique sauce...not for everyone, but I'm pretty sure they just passed 75 years in business, and folks from that area go back generationafter generation.