# Another track centers question

NW Mailing List nw-mailing-list at nwhs.org
Fri Aug 22 10:11:50 EDT 2014

```What about Z and G and 1.5"?  And, as I thought about G and the fact that several different scales use G track, I wonder should HOn3 and On3 use  N and HO or HO and O formula?  Just asking.

I have such a bad case of train nutisim that I have models in all of the scales mentioned except HO narrow gauge.  I seriously was hoping for a Z calculation, as I am just starting a layout in that scale.  I have to use a magnifier to work on it, but I'm giving it a shot.

And, since I brought up multiple scales; I have a display I take to shows which has several N&W boxcars with half moon herald. One each in Z, N, HO, S, O, and G.  If anyone has any knowledge on whether or not there was ever one in TT I would appreciate the information.

Bob Huston

---- NW Mailing List <nw-mailing-list at nwhs.org> wrote:
> Thanks Grant I do approve of your attention to detail
>
> regards
> Richard
>
> From: NW Mailing List
> Sent: Tuesday, August 19, 2014 6:54 PM
> To: nw-mailing-list at nwhs.org
> Subject: Re: track centers
>
> For track centers on curves:
>
> TCc = TCt + (K / R)
>
> should work for different scales and units of measure by scaling the term "K".
>
> For all terms in millimeters:
>
> TT3 (1:101.6) scale, K = 4300 [corrected from previous post]
>
> 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
>
> A 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
> ---
>     Main track centers on tangent (TCt) were 13' apart, later 14' (post-war) and wider in curves. For track centers on curves (TCc) in British TT (3mm) scale, try TCc = TCt + (5000 / R), where R is the inside track radius (all terms in millimeters).
>
```