BLI is using RMR (Arnold/Vlk) couplers for their recent N scale models

[ncbqguy]

BLI also did their own thing on the coupler. 
Another basic design principle that I set for the RMR coupler is the use of a metal spring for centering and closure.
The X2f horn hook-like integral cast spring may be cheaper to make but not acceptable if you expect it to reliably operate over years of use.

Charlie Vlk

[Cajonpassfan]

Clever. It doesn’t get much simpler than that. But no spring….so no bouncy bounce. I do hope Charlie’s concern about longevity proves to not be an issue. Time will tell. Still, a bummer when one’s design is compromised for the sake of expediency.
Thanks for posting.
Otto

[peteski]

The other problem with plastic springs is that they are in most cases too stiff to allow for magnetic (and delayed) uncoupling, although it seems that very few modelers use those features  nowadays.