Thanks Paul!
Your observation that code 110 and code 88 wheels will work on the same track, provided the same check gage is employed, explains the success of the current HO paradigm, where a combination of code 88 and code 110 wheels are used together on many layouts. Fred T -----Original Message----- From: Paul Vaughn <[email protected]> To: [email protected] Sent: Sun, Jan 23, 2011 12:02 pm Subject: {S-Scale List} Comparing wheel treads, some history All: I was the Sn3 Standards Chairman from 1979-1982. I developed the S standard for use with the code 110 wheel. Which became RP3 and RP4 in 1980. See the 1980 NMRA Special Bulletin. I was told by the NASG president at the time that I didn't know what I was talking about. The NMRA wheel size for S at that time was the code 135 which had the same size flange as the code 110 wheel. The code 135 wheel could still be used with my RP 3/4 if the S track gage was widened to 4' 8.5". As far as I know no one want to accept the wider track gage as it would iterate the Flyer people. That is the reason I was given anyway. The NASG had to change my RP 3/4 a little to claim they came up the their standards. They changed the flange way from 0.053" to 0.050" and recalculated the check gauges to claim authorship. S standard gagers at the time didn't even like the code 135 wheel set. Now we have the Flyer wheel set, the code 110 wheel set and the almost scale wheel proto 64. As I call it the code 88 wheel set. The code 110 & 88 won't work on the flyer track. The flyer wheels & the code110 wheelset won't work on the code 88 track. And the code 88(proto 64) won't work on the code 110 track. Why? Because, they all use different check gages. Note the code 88 wheel set will work with the code 110 wheel sets IF they use the same check gage. I use three wheel sizes, code 110, code 93 and code 88 for Sn3. They all use the same check gage and work equally well. When the car is on the track it is very hard to tell which car has what wheel size. I hope this has given some insight on what has transpired over the years. Paul Vaughn --- On Sun, 1/23/11, [email protected] <[email protected]> wrote: From: [email protected] <[email protected]> Subject: Re: {S-Scale List} Re: Comparing wheel treads. To: [email protected] Date: Sunday, January 23, 2011, 8:09 AM I don't have the NMRA recommended practices documents in front of me, but my recollection is that RP-25 is not scale dependent at all. in other words, a code 110 wheel with contour conforming to RP-25 would have the same profile whether used in S or HO. Would be glad to be corrected by evidence. The word contour is used to describe the various parameters that define the shapes of the tread and flange, and the curve (fillet) that connects them, along with the angle of the tread and the relative dimensions of the component parts of the profile of the wheel. Oh, and by the way, all model railroaders owe a huge debt of gratitude to those pioneers who devised the NMRA track and wheel standards and recommended practices--we are reminded of it every time a piece of rolling stock successfully traverses a section of track! Fred T -----Original Message----- From: Darrell <[email protected]> To: [email protected] Sent: Sat, Jan 22, 2011 1:36 pm Subject: {S-Scale List} Re: Comparing wheel treads. RP25 contour is not scale specific. But the flange dimensions, and to some degree the wheel width, are. Therefore an HO RP25 wheel is going to have a smaller flange contour than an S RP25 wheel. You have to pull up the different standards tables for the wheels you're comparing and check the different standards to see if they will be compatible. The NASG and the NMRA standards are all available online if you go to their sites. HO RP25 wheels are going to differ from BOTH S scale standards, but will be much closer to the Proto64 standards. Darrell --- In [email protected], "Tom Hawley" <t.hawley@...> wrote: > > ----- Original Message ----- > From: Darrell > . . . . . . . . HO RP25 wheels have a smaller contour than S RP25 wheels. . > . . . . . . . . . . Hope this hasn't confused you.... . . . > > > > > > > > > > > > > > It's probably confused a lot of us, though it probably won't make much > difference in our day-to-day modelling. What exactly do you mean by > "contour"? And which, according to your theory conforms with, and which > deviates from the "code 110" dimensions in the NMRA's RP 25? The various > codes in RP25 are not scale-specific, except that you have to find a code > that works with the S3 and S4 dimensions you're using. > > Tom Hawley -- Lansing Mich > [Non-text portions of this message have been removed] ------------------------------------ Yahoo! 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