Denny Anspach <danspach@...>
The Achilles Heel of prototypically narrow coupler boxes is that they inherently limit coupler swing, more if the shank pivot point is long, less if the pivot point is short. IMHO, this fundamental fact is what has held up companies otherwise favoring prototypical accuracy (such as Kadee) from moving in with all fours to adopt this naturally- attractive alternative. Less understandable in this mix is the continuing general tendency of suppliers to be overly solicitous only to those still dwelling in a dwindling HO modeling world of very short track radii.
The "Kadee Box" should be more accurately termed "Athearn Box" inasmuch as Kadee pragmatically adapted their coupler to the Athearn box of the '50s, which they judged at the time to be the de facto predominant installed-base coupler box . About a year or so ago, a review of couplers in one of the magazines judged a narrow box semi- scale coupler "unsatisfactory". When I challenged the author on his data behind this conclusion, I learned that all testing was performed only on sharp track 22" radius or less, a not-unexpected finding by itself, but totally misleading for so many of those pursuing the prototype modeling inherent with larger radii!
The attractive narrow coupler box within Jon Cagle's wonderful resin tank car kit (adapted to a Kadee #78) comes with a price: the long shank of the #78 coupler, further limited by the narrow box opening, * severely* limits the coupler swing. In this regard, this is not a model that would usually be attractive to most who will be favoring 18" curves. For those favoring such short radii in a prototype setting, e.g. industrial trackage, you may have problems, especially if two similar cars are to be coupled together.
As far as coupling/uncoupling on these curves with such cars, the operator may well have to manually center the couplers, just as in the prototype.
IMHO, this is just another area where the ongoing search for the "prototype" in appearance and operations should be moving us to adjust our thinking: e.g. advocating that the sophisticated models and accessories that we so favor, also be aimed to something well above the least common operational parameters.
Denny S. Anspach MD