The stated goal of this list is that "Emphasis is to be placed on
the study of the prototype with a goal of producing models of them
with as great a degree of accuracy as possible". To the extent
possible, that is also my goal on this thread.

There is not a single operational nor visual positive side to coupler
droop, and although I cannot speak for them, I will not believe that
Kadee, Sergent or Accurail (the only coupler manufacturers that I know
of who are actually thinking about such things, not merely producing
commodity knock-offs) would disagree.

However, all manufacturers (less Sergent) are all hostage to the fact
that although coupler boxes are made to a rough standard (the old
original Athearn box of the late '50s), in fact the coupler boxes can
vary considerably in depth, as do the thickness of coupler shanks.
The latter is even more variable when one considers that some coupler
shanks take into account the thickness of a sheet bronze centering
spring (even if the coupler does not need such a spring), while others
do not. As a result, the fact that any given coupler will in fact have
a smooth net fit in any given coupler box can be a crap shoot. The
Accumate Proto coupler is the exception (as I also believe the Sergent-
with-coupler-box) where the coupler and box are engineered as single
entity. As a result, they are the only couplers currently on the
market with no significant droop.

Shims can help, but required thicknesses can be surprisingly variable
(see above), and can also represent for the unwary modeler a lot of
pretty fiddly work.

We confuse operational practicality with prototype accuracy. They are
not the same thing.

As a matter of practicality or desperation, I may choose to (or HAVE
to) tow my freight cars with linked paper clips, loops of string, or
chewing gum around 9" horizontal and 45º vertical curves, but it
surely would be a stretch for me to assert that has anything to do
with prototype modeling (except detraction) (:-).

Denny


Denny S. Anspach MD
Sacramento