Mainline track spacing

[NW Mailing List]

Jim and Matt,

I understand this has been tested in "O" scale; however, the Class 
A/Jawn Henry stress test was not applied.

This was derived and reduced from equations in an old TE textbook of mine.

Grant Carpenter

On 4/22/2023 2:02 PM, NW Mailing List wrote:
> Jim,
>
> Instead of the constant K = 9 for HO scale, plug in K = 30 for O scale 
> (measurements in inches).
>
> Generally, for track centers (TC) on curves and R = radius:
>
> TC/curve/ = TC/tangent/ + (K / R)
>
> should work for different scales and units of measure by scaling the 
> term "K" below.
>
> For all terms in millimeters:
>
> TT3 (1:101.6) scale, K = 4300
>
> TT (1:120) scale, K = 3000
>
> For all terms in inches:
>
> N (1:160) scale, K = 3
>
> TT (1:120) scale, K = 5
>
> HO (1:87) scale, K = 9
>
> S (1:64) scale, K = 17
>
> O (1:48) scale, K = 30
>
> The disclaimer. . .
> I have only tested this empirically in HO scale. Your results may vary 
> with scale and tolerances of wheel gauge, track gauge, track centers, 
> and overhang.
>
> Grant Carpenter
>
> On 4/21/2023 6:08 AM, NW Mailing List wrote:
>> Grant,
>> What would be the formula for "O" scale . I too will be running the 
>> Jawn Henry and a Class A , and Y 's.
>> Jim Liddle
>>
>> *From:* NW-Mailing-List <nw-mailing-list-bounces at nwhs.org> on behalf 
>> of NW Mailing List via NW-Mailing-List <nw-mailing-list at nwhs.org>
>> *Sent:* Thursday, April 20, 2023 2:37:49 PM
>> *To:* N&W Mailing List <nw-mailing-list at nwhs.org>
>> *Cc:* NW Mailing List <nw-mailing-list at nwhs.org>
>> *Subject:* Re: Mainline track spacing
>> Grant, thanks for that formula for track spacing in curves. I have 
>> seen guidance and rules of thumb that fall with in the range that 9/R 
>> produces, but nothing that concrete.
>>
>> Matt Goodman
>>
>> > On Apr 20, 2023, at 10:24 AM, NW Mailing List 
>> <nw-mailing-list at nwhs.org> wrote:
>> >
>> > Mike,
>> >
>> > Per N&W Standard L-334 (1928, rev. 1947), track centers are 14 feet 
>> or 1-15/16 inches in HO scale. Rounded to 2 inches on tangents, add 
>> 9/R on curves, where R = the radius in inches. For example, the track 
>> centers in a 36-inch radius curve are 2 inches plus 9/36, or 2-1/4 
>> inches. Which main is less or more than 36 inches doesn't matter, as 
>> long as the centers are at 2-1/4 inches.
>> >
>> > This has been verified in testing and allows for the over/out of 
>> scale slop in track, running gear, car body swing, overhang, etc. The 
>> worst case sideswipe potential I can imagine is the inside overhang 
>> of the Jawn Henry on the outside main versus the outside overhang of 
>> the Class A boiler/smoke box on the inside main.
>> >
>> > Grant Carpenter
>> >
>> > On 4/17/2023 3:06 PM, NW Mailing List wrote:
>> >> Does anyone have info for mainline track spacing? Is it found on 
>> track charts?
>> >> From pictures, it appears to be approximately 13 feet center to 
>> center, but it's difficult to get a precise reading from this picture 
>> taken at an angle.
>> >> Thanks
>> >> Mike Rector
>> Browse the NW-Mailing-List archives at
>> http://list.nwhs.org/pipermail/nw-mailing-list/
>
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