With wishes that Marx trains survived, if they had, I think they would have had to
change for the market....i.e. convert to knuckle couplers (operating ones), and there
were Marx accessory Lionel compatible knuckle coupler that snapped on car axles.
This is like the catalog fantasies, but I'd think if Marx trains had survived, they would
be something like pre-Bachmann Williams. (what is the status of "New Marx", I didn't
notice them in the yellow hall this last time?) Of course, the cheap plastic last efforts
of Marx would not have made it to this day. In a sense, K-Line was the continuation
of Marx, and note how its products became better and better models through its life
span. Maybe K-Line rather than Williams is the better forecaster of the possibilities,
since they used some of the old Marx molds. My Marx tilt/fork couplers when a kid
worked much better than my cousin's prewar Lionel "latch" couplers. I don't remember that, as with Marx, I could just back up the engine and couple up, with
out manual assistance with the latch ones, but it has been a few decades.