Denny Anspach <danspach@...>
IMHO, there is only one way to check a proper coupler level, and that is to check the height of the coupler HEAD when coupler is actually LEVEL. There is no other way.
The common handy Kadee coupler height gauges that we all rely upon unintentionally fool us to think that only the height of the magnetic pin matters, because that is all that it really measures, leaving it up to the casual user to sight (or not) across to determine whether or not the coupler heads are actually aligned, and that they are level (not drooped)!
The Micro-Mark coupler gauge has a shelf to measure proper coupler head height, and I also have a similar coupler gauge of unknown parentage that effectively does the same thing.
Coupler droop is a major factor in determining coupler height because virtually none of the Kadee or clone coupler shanks fit tightly into the usual Athearn/Kadee coupler box (the interior height of which varies all over the map). Although such droop is minimized by the short shank couplers, and maximized by the long shank couplers observable droop can affect effective coupler head height by up to 0.040" (the total of two red washers, and one gray washer).
Judging droop can be misleading inasmuch as in normal repose a given coupler might well stay level, but under tension coupled in a train, unwelcome inherent droop may well become evident as either promoted by draft angle, or one or the other of the heads of the adjoined couplers is not at the proper height. The ultimate price paid by the unwary in this regard is when the coupler judged to be OK on casual measurement on the coupler gauge is pulled down when under tension, and the magnetic pin catches the next closure rail pitching the cars off on to the floor (how do I know?).
Managing or eliminating coupler droop is for another post, but in short, this ubiquitous (understatement!) problem will not be eliminated until manufacturers decide that their couplers and coupler boxes need to be engineered together as a functioning unit. At the moment, only the Accumate Proto coupler/box is so engineered.
My closing advice that if the critical modeler will meticulously address with each piece of his rolling stock both the maintenance of accurate coupler head height, and the minimizing of coupler droop issues, visually-satisfying trouble-free operations will surely ensue. By doing so, IMHO, we can also at last eliminate the current flow of countless cars passing by jacked up on washers and bushings, as they were in flood pants :-).
Denny S. Anspach MD