Re: New Coil-Elliptic truck

Dennis Storzek <destorzek@...>

--- In STMFC@..., Andy Carlson <midcentury@...> wrote:

Tom, I am guilty as many others in semantics, particularly when it comes to RR terminology, but this is quibbling. Semi-scale wheelsets are .088 " wide, so many times they are refered to "code" 88. There are no other wheelsets available in the commercial market with a confusingly similar notation, so do not worry about the choice of words.
That is simply not true. "Code 88" is the designation specified in NMRA RP-25 for a wheel made to specific profile, and NWSL, among others, makes wheels that are indeed that profile. The IM and Reboxx are not, and therefore are not Code 88 wheels.

NMRA RP-25 specifies ONE profile that is made proportionally larger or smaller to suite the scale. Since the same size profile could conceivably be used for more that one scale, the NMRA used an arbitrary designator, CODE nnn, nnn being the width of the wheel, similar to how they designated rail, which is also multi-scale. However, the NMRA never intended wheels of different "CODE" sizes to operate on the same track. That is an adaptation that modeles made when they noticed that it happens to work, kind of.

Now, as it turns out, there are a lot of reasons why the IM and Reboxx .088' wide wheels with flange dimensions that match the NMRA Code 110 wheels are more desirable. Since the flanges are exactly the same as the flanges on the wide wheels, flangeways can be filled to allow the flanges to be supported by the bottom of the flangeway, thereby eliminating the "bobble" when crossing frogs. But, there needs to be a different designation of the Reboxx semi-scale wheels, so they won't be confused with real, correctly proportioned NMRA CODE 88 wheels, which for our purposes are actually less desirable.


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