As I reported earlier, there is no continuity of design. The engineers and producers are different every time. It might even be a different factory every time.
Regardless of engineer/ designer. Lionel has reused tooling multitudes of times. The only things that really change are the electronics.
This truck/ coupler debacle is the result of a tooling change.
The trucks/couplers were the same design for at least a decade prior to this newer design with these issues.
No one seems to know what happened to the tooling for the "quality" sprung die-cast trucks with the hidden uncoupling tab and articulating coupler.
Maybe Lionel should try to "aquire" MTH's sprung trucks . They are a very similar design to the original ones Lionel was using.