Denny Anspach wrote:
"Who continues to use Kadee #4s today? Well those of us who delight
in restoring to new use old cars from the '50s; and an unknown number
of you out there who love the springy slack action that results from
the actions of a string of these cars. However, attempting to insert
a tiny filler piece inside one of the tiny coupler shank springs (to
reduce run-out), and then inserting these springs in place for and
aft of the coupler box post while holding the whole assembly together
is a balancing act not for the faint hearted- and I avoid these
couplers whenever I can do so."
From an operational standpoint, I really liked the old #4s. This
spring design gave it a reliable centering action superior than that
provided by the stamped leaf spring of the #5.
FWIW, my $.02 on the #58 - I think it's wasted when you mount it in
the "Athearn standard" #5 coupler pocket, because now it really draws
attention to the fact that the draft gear is too wide and shallow. I
feel that the net improvement in appearance is zero.