Early on I made a change to the track plan from double deck to a single deck railroad. When I made that change, it caused Bottleneck yard to have some problems as there was two tracks adjacent to each other but at very different elevations. I also encountered some derailings on the switch entrance to Rock Ridge yard which follows Bottleneck on the layout plan. My solution is to re-route the track slightly to provide some horizontal separation between Bottleneck and Summit so that I can construct a hill and other scenery in the area between Bottleneck and Summit. I’ve decided this will allow a nice opportunity to provide a long tunnel which will serve as the new entrance to Rock Ridge yard, eliminating the troublesome yard entrance switch that derailed some rolling stock. All in all it looks like a lot of improvements with only a very slight expansion of the width of the railroad along the North wall. Construction has commenced.