Eventually, by 1964, Arnold rapido equipment came equipped with the coupler that we now know as the “Rapido Coupler”. At the same time, Minitrix was using a “Baker” type coupler.
But what happened next is crucial to the development of the entire N-Scale sector of the model railroad hobby. For reasons unknown, Arnold allowed other model train manufacturers to use their coupler design. Although some texts point out that the other manufacturers made minor changes to the basic design so that they would not infringe upon Arnold’s design, other texts and individuals who have studied the history of N-Scale indicate that Arnold willingly shared its design.
In any case, reference to the “Rokal License” ended with the 1966-67 catalog; at the same time, Rokal itself was going into bankruptcy and would shortly disappear from the railroad manufacturing scene.
Regardless, the Arnold rapido design was inexpensive to manufacture and reliable in operation, all other model train manufacturers quickly took up the Rapido coupler, which, in turn, allowed for the very quick growth of the N-Scale sector of the model railroad hobby.
In time, other more realistic designs took the place of the Rapido coupler, but one has to wonder what would have happened to N-Scale if the coupler design had not been given away by Arnold.