Tunnel (Main St., 1899) across Main St. in Irwin, Westmoreland County, PA. Center Hwy (becomes Pennsylvania Av.) E. 0.3 miles from jct with US30 on the W. side of Irwin, N. on Main St. 0.5 miles to the tunnel. (8-4-06, N40 20.11 W79 42.57) Photos by Jack Schmidt.