The rendition below of the CAD drawing of my track plan shows the various towns and areas I modeled in this layout. Some of the names are from real places in Pennsylvania, but absolutely no attempt was made to model the real world. This is a purely fictitious layout.
I use Abracadata's 3D Railroad and Design software to design my layouts. I struggled quite a bit trying to get a design into the available model railroad room (a spare bedroom). The room is 11'-8" x 10'-4" (3.55 x 3.12m). It has a standard bedroom closet in it that was very tempting. The closet, however, turned out to be useless for the railroad itself and was used for household and model railroading materials storage only (the radius for getting in and out of the closet was going to be too tight). I wanted a continuous-running layout for this layout. I also wanted to be able to run at least two trains, and hence I created a double-track "bowl" design. The double mainline line followed the perimeter of the room in a rounded-rectangle design. Along three of the four walls there are opportunities for industrial switching in the future. The diagram below shows the benchwork with the track plan super-imposed. The track height of the upper level was at 62.5 inches (1.59 m).
This diagram shows the planned major scenic features of the layout. This is using the latest track plan.
This diagram shows the lower level with the the ten-level helix. It is a large storage yard, so that I can bring up whatever train I want to the main layout. Grades on the upper level did not exist, but the helix was 1.75% on the outer loop, and 1.95% on the inner loop. Total trackage, including the yard shown below was 407ft (124m) actual, 12.33 miles (19.84km) scale.