I have a steel mill on my layout with a blast furnace that isn't really served by sidings. It rests against the backdrop so its suggested that the track for coal and ore cars lies behind it. I thought it might be fun to support this concept with a visual so I constructed a highline that travels along the backdrop and appears to duck behind the steel mill complex. It starts in a corner of the layout with a real HO engine and cars. The second hopper is cut at an angle so it seems to travel into the backdrop.