The first tunnel we enter is Tunnel 6, the summit tunnel. This tunnel was carved by hand through solid granite in the mid 1800s. Average progress was about six inches per day. In addition to working from both ends, in order to reduce the time required a vertical shaft was carved at about the mid point of the tunnel so that work could proceed on four faces at once. Upon completion, a steel cap was placed over the top of the shaft. This cap is visible from the old Hiway 40.