I just started working on a diorama based on the Cross Junction / Corsa area of John Allen's Gorre & Daphetid railroad. I bought the plans from Silver Ridge Modelworks. It's available as either an HO-scale laser-cut kit, or you can just purchase the instructions and the templates, and build it yourself from scratch in whatever scale you want. My plan is to take the templates and apply Clever Models textures with The GIMP to make an N scale version of the depot, and install it in a diorama which is similar to the original G&D scene.
Here is the diorama suggested by Silver Ridge...
...and here is how the station looked in the original G&D setting.
You can see that Allen had a tunnel perpendicular and under the upper track. I decided to put that in.
I threw together a quick, corrugated and chipboard dummy in three dimensions to see what the proportions might look like. This gives me some planning flexibility, because I can move the station around, and I'll have an idea what works and what doesn't.
This is what it looked like after a couple hours.
I converted the measurements for the diorama down to N from the Silver Ridge plans, but when I got to the station, I used no measurements at all -- I just hacked away at the chipboard and slathered the edges with Aleene's Tacky Glue. If someting was too big, I chopped it off. If it was too small, I tore it off and made a bigger piece. It's a bit like sketching with a pencil and erasing whatever looks wrong. It's a lot of fun, and the whole process only took a couple hours. Possibly 90 minutes. I'm having trouble estimating the time spent, because I was "in the zone" the whole time.
The following evening, I threw together a very rough cityscape, similar to the G&D original, but a little more urban. I'll use forced perspective to fit that skyline in the very limited space, and the buildings in the front may need to be a little smaller than N scale.
I can already see I'll have to lower the skyline about 1/2 to 3/4 of an inch, because I don't like the proportions. Also, I'll modify that cross street so the back of it is hidden a bit better.
The upper deck of this should have a streetcar, while the lower station will provide passenger and freight service.