Most of my original Marx are 8 wheel, either scale or 6". What to do for cabeese when running the post war KCS, Monon or Seaboard diesels. Convert some cabeese to prewar frames of course, but then a transition car is needed to get the diesels tab couplers to work with the cars.
Here are my cabeese for the diesel's
Caboose, diesels and the transition car.
Transition car, slot coupler on the front and a female one way at the rear.