Main Lining in Chicago. We have been receiving plenty of calls about the Perma-Main Lining “Top Gun” in and around the Chicago area. The Perma-Main Lining “Top Gun” has been featured in trenchless technology publications in Chicago and around North America. The Perma-Main Lining “Top Gun” uses air inversion instead of water and currently performs continuous main lining on 24-inch diameter pipe. If you live in Chicago and would like to see an in-ground main lining installation, please call us anytime to schedule!