Last weekend, I started laying standard gauge O scale 2 rail flex track on this layout. After diligently trying to get nice wide curves, I discovered that none of my scrathbuilt rolling stock would negotiate them without binding up. Luckily, I haven't invested in any working locomotives yet.
The On30 track is on the way. My standard cars will be on static display at the left of the layout in an interchange area with the narrow gauge. I plan to model a whimsical late era South Pacific Coast line that never got standardized. The far end of the layout will be inside a long tunnel under part of the city. I am still fleshing out the track plans.