(Good job with the smiley!)
If you said "my Fn3 Coeur d'Alene Railway and Navigation Company railroad" then I would have known exactly what you meant. All the rest was superfluous.

Just as "HOn3" = a 1/87th scale model 3' gauge RR.
I suppose that to someone that already knows what "Fn3" means, then it has meaning. I have never been able to memorize the various letter equivalencies to scale

, so it has zero meaning to me and adding the various suffixes just cornphounds the cornphuzion. I would have to ask, "What scale is that, what track gauge does the model run on, and what is the prototype gauge?"
Yes, a shortcut is a wonderful thing, BOIYKWIM.
But then saying the gauge is 45-mm is also somewhat lost to many people if they normally use 'inches' (i.e.: are 'metric deficient'). And, of course, for some people, you have to hold your hand out with your fingers "oh, 'bout that far apart" so they have some idea what 1.75-inches is, or tell them it is slightly bigger than the train that ran around the Christmas tree in the 1950's.
("HOn3" is a typo about putting a sharp edge on your razor.

)