The under the rails one works reliably.
My prior layout, all locations were accessable by hand, so I always used the uncoupling pics.
Next layout just might have a electro-magnet on a passing "run-around" siding....
Ricky W.
HO scale Proto-freelancer.
My Railroad rules:
1: It's my railroad, my rules.
2: It's for having fun and enjoyment.
3: Any objections, consult above rules.
For me, it's nay.
I used between the track uncouplers but they caused more unwanted uncouplings than wanted!
I removed these and started using the Rix uncoupling tool. As someone else mentioned, it immediately wants to grab the nearest handrail, grab iron, etc.
I switched to the bamboo skewer. Price was right, uncoupling was easy.
I now clip the pin from all couplers. I add brake hoses to all cars and I didn't like the look of the extra pin.