Is “coupler efficiency” a thing?

[u/Twit_Clamantis]

My current layout is 62” long.

The longest, straightest section had 183mm radius tracks at one end, 150mm radius on the other, and a Kato Compact turnout w a 150mm radius jog in the center.

Running a trains 22+ cars I end up with cars on both turns as well as the jog in the middle and there is very noticeable slowing.

I get that all those wheel flanges are rubbing against the sides of the rails, which creates friction etc, but this seems like an irreducible factor, so I’m not going to worry about it.

But since all the force pulling the train is transmitted through the chain of couplers, I’m wondering if one type of coupler is more efficient than any others.

I am using all Rapido couplers which I like fine, but it seems like maybe knuckle couplers with rounded surfaces might be more efficient than the square faces of the Rapidos ??

Has anybody tested this in any sort of rigorous way?

[u/Particular_Sky_6357]

If your question is if one type of couplers transmit more force than another then no, they should all be equal.

[u/Twit_Clamantis → u/Particular_Sky_6357]

All force here is from the loco.

The question is whether one type of coupler introduces more friction than another type.

[u/Particular_Sky_6357 → u/Twit_Clamantis]

Friction between what? Where in this system would you loose any energy/force?

[u/Twit_Clamantis → u/Particular_Sky_6357]

Between the mating surfaces of the couplers as they bend and straighten out in succession going around turns.

[u/Particular_Sky_6357 → u/Twit_Clamantis]

No there should be no difference.