I have been using the Kadee #58 & #78 for a couple of years and have no
problem coupling and uncoupling with the few cars left with #5s. I use both Mc
Henry and Kadee under track magnets and they work very well uncoupling. The
McHenry is less than half the price of the Kadee by the way. Even the cars bought
new with knuckle couplers like Walthers and Athearn couple with 58/78 with no
problem, although I change them over to the new couplers for operation.
I heard one modeler in a hobby shop comment that he couldn't use the new
couplers because they continually kept uncoupling. I would love to see his
track work as that has never been a problem with me.