Cool image, Bill! I was using Terraserver yesterday to see the layouts of some yards long a section of UP mainline I've been thinking about modelling.
In a nutshell, the idea is this: model the stretch between Taylor, TX and Hearne, TX. Taylor is a major agricultural town. It has a small yard with a wye. Moving towards Hearne (along U.S. 79), are Thrall and Thorndale. Both are also ag towns, too, but they're are a lot smaller.
Continuing down the line is Rockdale. Just before reaching Rockdale, the UP mainline meets up with the Rockdale, Sandow and Southern Railroad. The RS&S was originally created to service a lignite mine, but the mine failed. Later, Aluminum Company of America (ALCOA) bought it and now uses it to ship their products (aluminum ingots and powders).
Hearne is at a crossroads. There is a yard on the "other" line, but I was thinking of maybe making it part of "my" line. Also, there is a car servicing facility there that would make a nifty staging area!
This line was formerly owned by Missouri Pacific. It crosses over four other mainlines in this stretch (including the BNSF). Valley Junction, a few miles to the west of Hearne, is in the middle of another farming region. There is a silo right at the crossing!
Most of the traffic is intermodal, autos and some kind of ore/gravel. I don't know if there is much going on locally. I still have a lot of research to do!
It will be a long while before I start working on this layout (if I do it at all). It's going to require a lot more space and funds than I have available right now!
-Rory