As close as I can measure, the wheels on mine appear to be 1 inch diameter across the flanges at their very widest (farthest inside) and 13/16 across where they roll on the track, making them a scale 39 inches diameter. 36 inches would be 3/4 inch, so they appear to be 3 inches too large. May be they are a bit too large, but the units look fine to me as to height, but that is often something a person has to judge for themselves.
Real railroad wheels are NOT measured "across the flanges", but across the tread of the wheel. Thus, the wheels on an "E" type locomotive (ANY "E" type) should be NO LARGER than 38 inches in diameter, for Rock Island and DL&W units, while all the rest of the railroad "E" type units had 36 inch diameter wheels.
Freight units of the earlier era, all had 40 inch diameter. Now modern, AC traction units had/have 42 inch and 45 inch diameter wheels.
