Yesterday we began "reverse engineering" the tunnels on the northeast corner of the property. Normal engineering requires tunneling through existing mountains. In this case, we have a reverse process starting with a flat elevation 25 feet above the track on the lower level, we install the tunnel portals and then start building the mountain. The portals and basic mountain structure were design and temporarily set in place. The plan is the glue the sections of the mountain together so it can be removed if necessary. This will be quite the engineering feat if it works.