Denver was a major hubub of railroad growth, I was in a club building an HOn3 line and I was searching for a practical real railroad that matched the locale of the model railroad (west coast major railroad line but fictional something like the UP)
I found the Denver, Laramie and Northwestern, but it was standard gauge, not 3 foot as there were around Denver. Parts of it actually built and operated, and parts were graded north. The Club modeled Laramie but was unfinished so we were in planning phases but part of the HOn3 got built. Unfortunately the club had to move so never done.

Anyways, the real railroad never was finished, if you are out there, you may find the grading work still exists. (now I know how it feels....)