"Andre, your account of the advent of the Diesels that did it on the KC&G is so realistic I was sure I would find the railroad listed in the Official Guide."
Like I shared above: Mom always said I had an over-active imagination!
I think there's been some minor refinement of the roster, but 99% of what you read is still the straight poop in regards to the KC&G roster.
I thoroughly enjoy the research that one can expend on their concocted theme. From the git-go, my goal for the KC&G was for the theme to be as plausible as possible (that is, plausible to my demented mind). I've managed to do that to my satisfaction. Whether others find it plausible is up to them to decide. The most important one needed to be satisfied (me), is indeed.
I also thoroughly enjoy creative writing about railroading. I enjoy incorporating experiences I've had personally, or railroading friends experienced, or I've read and/or viewed in railroad media, and such as that. Helps to give my theme a life of its own, as well as builds "depth" to my theme. Shucks... even the characters I concoct help to bring it alive in my mind! (And I've known some characters in railroading!)
There you go. Use that God-given imagination to come up with a theme that is first and foremost fun to you, and that is plausible to you. Accomplish those two goals and what others think won't be a priority. Sure, it always adds to the fun if others get on board with what you're doing... but the basic core of the theme must trip your trigger. No one else's.
My region is in the midst of a winter storm that is quite different from what we're used to: Blowing snow with temps down toward zero Ferenheit with wind chills well below zero. Seems to me for a perfect day to be piddling with my trains in some form!
All fer now!