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 Post subject: O scale dual gauge?
PostPosted: Tue Apr 21, 2009 2:26 pm 

Joined: Thu Aug 07, 2008 10:24 am
Posts: 26
I'm almost afraid to ask, but what's the chances of getting an O gauge / On30 (not On3) dual template?

Basically, the same thing as model DK-HO-HON3-T-6-L-ME55 is in HO, but in O/On30

Since On30 is the same track width as HO standard gauge, it seems it would not be an huge engineering undertaking.



 Post subject: Re: O scale dual gauge?
PostPosted: Wed Apr 29, 2009 1:58 pm 
Site Admin

Joined: Fri Mar 26, 2004 1:26 am
Posts: 196
Location: Brantford, Ontario, Canada
The chances of releasing O/On30 Dual Gauge tools and supplies is slim to none at this point. We would not be able to produce O scale QuickSticks, and the time and effort to produce dual gauge tools is considerable. We have no plans on expanding the dual gauge line in the foreseeable future.

 Post subject: Re: O scale dual gauge?
PostPosted: Tue Mar 27, 2012 8:35 pm 

Joined: Tue Mar 27, 2012 8:56 am
Posts: 1
I am having difficulty finding even the simplest of track gauges and tools for hand-laying O and On30 dual-gauge. I can find a Code 100 metal 3-point track gauge for HO/On30, but not for O Scale 1.25" gauge. Alternately, I can find Code 125 in O scale, but not in HO/On30.

So, I am re-visiting Fast-Tracks as an alternative, but your previous reply indicates I would not be able to find what I need for 1/2 of my railroad. I thought others would have found O and On30 dual-gauge as a natural combination. Apparently not. Have you had any other inquiries on this?

Anyhow, my question is, would it work to lay a 3rd rail on the same ties as your On30 templates provide for? If so, how would I hold it and keep it accurate?

Nick Plate

 Post subject: Re: O scale dual gauge?
PostPosted: Wed Mar 28, 2012 12:44 am 
User avatar

Joined: Sat Aug 13, 2005 10:48 am
Posts: 365
Location: East Texas - USA

Standards for O (1.25" gauge) and the On30 (.649" gauge) do not match in flangeway characteristics because the wheel profiles of the two gauges are not consistent. Dual gauge has several interchange points and common paths in the trackwork, but full operational reliability does not work well when non-interchangeable common wheel standards are applied. This is a common problem with dual gauge operations for most scale combinations. Dual gauge trackwork has to have compromises biased for either the narrow gauge or the standard gauge or re-equipping wheels for one or the other gauge is deemed appropriate.

Only where the wheel profiles are reasonably close in compatibility can trackwork be constructed for operational reliability. Even with O and On3, there are issues of compromise that have been required for interchange. The older RP3 and RP4 of the NMRA Recommended Practices attempted to resolve just the issues - but created a tightened standard gauge specification that was otherwise incompatible with just the 'regular' standard gauge. That is the principle reason the RP3 and 4 have been completely obsoleted. You will have to go 'fine scale' with the standard gauge to become compatible from an operational interchange with the narrow gauge.

It's not a simple engineering consideration.


-ed mccamey-
COSLAR RR - http://www.coslar.us/
NMRA Standards and Conformance Department
PROTO & FINE Scale Coordinator
I estimate I have about 5 pounds of coupler springs somewhere in the vicinity of my workbench.

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