(CN-Park Rd.) under CN RR SW of Clinton, Tunbridge Townhip, DeWitt County, IL. IL54 SW 4.15 miles from jct with US51 on the W. side of Clinton, W. (curves NW) on Park Rd. 0.1 miles to the tunnel. (N40 07.108 W89 03.315) Photos by Jack & June Schmidt 9-4-19.