Board of Water Supply. City Water Tunnel No. 2. Patrick McGovern, Inc., contractor. Special wooden form for construction of the concrete lining for tunnel. The form was completely erected in the contractor's yard and was built so that it could be taken apart in sections for transportation and handling. This photograph is a view of the form as erected in the contractor's yard and shows the circular and elliptical ribs covered with lagging of narrow wooden strips which were steamed and bent to the required curvature. March 25, 1932.