…or is that inches?
Perceptions are very important in model railroad design. Unless you are designing or building a switching layout, most layouts are intended to depict a railroad that goes somewhere. In all but the most generous of spaces, that means we need some way of getting extra length of line into a given space. Double decking has become a typical means of doing so, but there are times where parallel lines on the same level of railroad are needed.
The key question then, in our struggle to show a line “going somewhere” is how to visually separate those lines. A six inch horizontal separation, as in from the mainline to the second yard track in the shot below, is very little in visual terms.
When we get into the vertical dimension, as in the next shot, 6 inches is a significant difference. I’m not sure why, but the vertical is an excellent way to separate parallel lines, which are schematically separate.
Another factor is to figure out what draws the eye into a scene. In my opinion, this is an area where model railroads have a distinct advantage over a static diorama. The motion of our trains is something that captures our eyes and attention. Considering the shot above, a static picture allows the eye to see the whole scene, and notice both lines through the scene (which are about 3 or 4 train lengths apart on the layout. When viewing the scene in person, the motion of a train catches the eye, and we tend to focus on the train, and the line it is on. My experience in looking at this spot tells me that I don’t even notice the other line, even though the bottoms of the bridges are very close to the lower line, especially when there is a train passing through.
Because of this, I’m not concerned with designing a double deck layout. If a 6 inch vertical separation is visually adequate, I’m not concerned about a second level of railroad being a distraction when viewing the layout. How much is enough separation? I’m not entirely sure, I’m going to have to do some mockups before too long to see how deep a deck works (at this point I’m assuming 24″ wide shelves stacked over each other will work) and how far apart they need to be. I should also test closer spaced tracks, with a small, inch and a half or two inch vertical separation. That would allow a physically close, yet schematically distinct, industrial district (for example) I could also use this sort of idea around the smelter, or mining areas of my plans.