This was a great deception because I counted much on this trucks for my projects. You may say that I must avoid sharp S-curves, but what is a trolley freight operation without sharp S-curves?
Finally, by "try and error", I found the reason. The Kadee truck with their real three piece articulation needs a wheel staying well in the rail and who doesn't mount.
Kadee with simple plastic wheels
The surplus Kadee wheels can be reused in a rigid bogie like the Tichy Train Group plastic arch bar truck. Nothing is lost, everything is transformed.