We're all read articles, blogs, posts, etc., about the top locomotives in every category: size, weight HP, tractive effort, etc. Often there is not agreement on what loco is best in a category, but that is okay with me: certain the top two or three contenders cover it regardless of viewpoint.
I tried to find a list or "top" selection rating of the outstanding locomotives from the owner's standpoint: reliable, durable, easy and cheap to operate, efficient with fuel, stable at speed and easy to drive, and requiring low maintenance and easy maintenance (no third cylinders, etc). Very likely the top candidates would be locomotives made in significant numbers, and that is fine with me. I doubt any loco made in just ones or twos no matter how impressive otherwise (e.g., triplex) is a candidate, but I suppose UP only needed a few dozen Big Boys, so the fact that only a few dozen were made does not mean it would not be a candidate if it was low cost and easy to own for its size.
Have anyone every seen a list of what the best locos were from a RR ownership/business standpoint? That is, after all, what the RRs bought them for.