Back in the old Ohio Electric days ...

Ohio Electric wooden Boxcar with clerestory roof

HO scale wooden boxcar, laser cut body and frame, 3D printed roof, Kadee #501 trucks, Sergent couplers

Sergent H0 knuckle couplers for Interurban operations

Some modelers advised me to try out  Sergent H0 knuckle couplers.

http://www.sergentengineering.com

I am not disappointed at all, they are not jackknifing, prototypical and finally easy to install. Mounting the tiny cast parts is a little challenge of surgery, but not so difficult in the end.

They are mounted on self made drawbars, 3D printed like the rest of the underframe. I will made this drawbars soon available for all my models.