Perhaps you already have this information. The original Athearn RDC-1 aroused so much interest that MR covered it twice in Trade Topics in 1953. In the June '53 issue they simply had a photo and the review such as it was essentially just said "it's here."
The August '53 issue had a photo on the cover -- that is how important it was deemed -- and the blurb said "How Does the New RDC Run?" But due to an error Trade Topics did not review the RDC. This caused no end of joshing in the RPO section in September. One guy wrote "apparently it ran so well that it ran right out of the magazine." Another guy: "could it be that the new baseball team you have there in Milwaukee [the Boston Braves had moved to Milwaukee and were getting record attendance in their new home] is distracting your staff?" Still another: "I give up. How does the new RDC run?"
Yes it finally did get reviewed in the September '53 issue. The only criticism (the shorter than prototype length was noted) was how it ran -- minimum scale speed of 35 mph. $14.95 powered, $6.95 unpowered. The review does go into some detail as to the drive train.
Dave Nelson