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<div dir="ltr" data-setdir="false">Steve, Here's a link to NMRA standards for track centers---it's diff depending on era and of course if tangent curve or not ----<a href="https://www.nmra.org/sites/default/files/standards/sandrp/pdf/rp-7.1_tangent_track_centers_and_clearance_diagrams_2019.01.pdf" rel="nofollow" target="_blank">https://www.nmra.org/sites/default/files/standards/sandrp/pdf/rp-7.1_tangent_track_centers_and_clearance_diagrams_2019.01.pdf</a></div><div><br></div><div dir="ltr" data-setdir="false">Tony-- Our O scale is 1/48. The British use a a 7 MM scale that is close to 1/43. It's the track gauge that is a mess in "O"scale ---a real rabbit hole. The short is that a wrong gauge was used back in the 20's - 30's that was rounded up to inch and a quarter from the correct 1/48 scale (1.25 inches actually scales 5 feet instead of 4foot 8 &1/2 " ) . various attempts have been made to correct this by changing the scale or the gauge or both, What has been pretty much settled on is US O scale = 1/48 and 1.25 " gauge for most models and a smaller group that does "Fine scale" or "Proto 48" that is 1/48 with a gauge of 1.177 min -1.203 max . I'll PM you because your model drawings need a longer explanation. (And you other guys, No, I don't want to argue about it or be better informed. --add smile emoji here)</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">JJ</div>
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On Monday, November 8, 2021, 10:11:14 AM PST, ACCRS O Scale list <accrs-o@mail.accrs.org> wrote:
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<div><div id="yiv1612566206"><div id="yiv1612566206yqt53133" class="yiv1612566206yqt5889747090"><div><div>I am working on a plan for a small O scale layout. Could someone remind me what the distance between track centers and what the vertical clearance should be? I have been using 4 inches for both.<div><br clear="none"></div><div>Steve Bull</div></div><br clear="none"><div class="yiv1612566206gmail_quote"><div dir="ltr" class="yiv1612566206gmail_attr">On Mon, Nov 8, 2021, 10:04 AM ACCRS O Scale list <<a rel="nofollow noopener noreferrer" shape="rect" ymailto="mailto:accrs-o@mail.accrs.org" target="_blank" href="mailto:accrs-o@mail.accrs.org">accrs-o@mail.accrs.org</a>> wrote:<br clear="none"></div><blockquote style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;" class="yiv1612566206gmail_quote">Message From: Tony Long <a rel="nofollow noopener noreferrer" shape="rect" ymailto="mailto:tony.long@outlook.com" target="_blank" href="mailto:tony.long@outlook.com">tony.long@outlook.com</a><br clear="none">
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<p class="yiv1612566206MsoNormal">I have a question on O scale measurements and wanted to check with others.</p>
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<p class="yiv1612566206MsoNormal">Conversion – what is the correct conversion for 2 Rail 1:48 scale. I’ve seen it listed as 1:43.5</p>
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<p class="yiv1612566206MsoNormal">Using that then the spacing between rails for 4’ – 8.5” comes to 32.99 millimeters. I don’t have any two rail O scale track here to check that. Is that correct? Using 1:48 comes to 29.90 millimeters.
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<p class="yiv1612566206MsoNormal">Millimeters is what I want to sketch with.</p>
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</div></div></div>Message From: Steve Bull <a shape="rect" ymailto="mailto:sbullfox@gmail.com" href="mailto:sbullfox@gmail.com">sbullfox@gmail.com</a><br clear="none"><br clear="none"><div class="yqt5889747090" id="yqt85132">_______________________________________________<br clear="none">Accrs-o mailing list<br clear="none"><a shape="rect" ymailto="mailto:Accrs-o@mail.accrs.org" href="mailto:Accrs-o@mail.accrs.org">Accrs-o@mail.accrs.org</a><br clear="none"><a shape="rect" href="https://mail.accrs.org/cgi-bin/mailman/listinfo/accrs-o" target="_blank">https://mail.accrs.org/cgi-bin/mailman/listinfo/accrs-o</a><br clear="none"></div></div>
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