I opened up my 30-1660-1 P&LE (NYC) 0-6-0 USRA Steam Switcher #9060 PS3 and twirled the tach wheel. I counted 18 revolutions for one rev of the driving wheel. The blind drivers and non-traction tire wheels are 27mm. Again the traction tire increased that a little bit to 27.2 mm. Tach tape has 24 stripes.
My goal along these lines is to figure out how to decode the data returned by the engine that represents the trip odometer (DTO) and odometer (DOD).
In the next few posts, I will describe what I have discovered so far.