I'm primarily an HO railroad modeler (mainly because that's what I have - the momentum factor), but I confess I'm mesmerized by the "bigger stuff". I own a locomotive and a caboose in "S" scale, and a locomotive and a boxcar in 1:29 ("G") scale. To come to the point: I own a brass HO scale Southern Pacific AC-9, and I really enjoy having it, but if I could find an "O" version, like the Biblical "pearl of great value", I'd probably sell the HO model and whatever else I'd need to in order to own the "O" locomotive, and I'd might even switch to "O" altogether. I know Lionel made one a few years ago. I assume it's three rail. Does anyone in this community know how "faithful" a representation it was vis-a-vis the prototype? (I know that a lot of Lionel's trains have been "adjusted" in terms of dimensions, etc., in order to run on the smaller radius track some folks use.) Does anyone know of a dealer who might have or be able to get an AC-9? This next question will show you what a newbie I am at "O" related matters: How hard would it be to convert a 3-rail locomotive to 2-rail? Thanks for indulging me!