Fundamentals before you design a track layout:
What do you want?? Basically, a toy train layout that has lots of track, and accessories crowded in, like back in our youth? Or a depiction of a railroad in miniature?
The average model structure is really a caricature of the prototype. A scale model of Grand Central Terminal in NYC in 1:48th (O scale) would be 48" long X 22" deep X 22" high- and this does not include any trackage. To put such a structure on a layout requires a lot of space.
Highways and roads for scale cars, in O need to be 6" or more wide- and take a surprising amount of space. So, we in model railroading use visual tricks to make the layout seem bigger, but there are limits to how that works. All this needs to be in the plan.
- You have to leave aisles to walk around/ in the layout, plus;
- you have to have access to all parts of it. So- for example, any section that is against a wall has to either be about 24- 30" MAX deep, or have a removable/ lift-able access hatch for maintenance.
- You have to allow for access to things IN the train room- if the furnace needs to be replaced, do you have to dismantle the train to do it?
- Windows- can be a distraction if they are behind the train layout.
- Access to work bench for working on trains- you wouldn't want to have to go up to the attic to work on an engine then test it in the basement.
- support columns - if they exist how do you hide them?
And dozens of more compromises and considerations. I sent the drawing of my space to the track designer, first, after discussing what I wanted.
