The present road cutting at the summit of the hill was constructed in 1968, eliminating a tunnel started pre-World War 1. This tunnel was not finished until about 1923 as the work had to be postponed because of the hardness of the papa and the War.
There is walking access to the tunnel by following the line of the original cutting. The return trip will take about 45 minutes.
There is more information on the nearby Heritage Trails noticeboard.
The cache is a bison tube.