# Track Layout Guidelines - Elevations, Spacing, Etc.



## dindallas (Dec 12, 2016)

I am using Post War, O gauge, tinplate track and accessories for my layout. I want to use as many accessories as I can on a 5' by 9' layout. I have a plan done in SCARM but when I roughed it out on the actual base, it did not all fit. Several of the O22 switch motors get in the way of other items and some of the larger accessories (456 coal ramp, 97 coal loader, 164 lumber loader) are causing some conflicts because of physical size or spacing required between tracks.

Where can I find some guidelines such as:
1. Minimum spacing between adjacent tracks?
2. Minimum height between levels of track so one train can safely pass underneath another level of track?
3. Maximum grade or number of 10" track sections required to attain a second level to allow one train to pass underneath another?

I am sure these questions have been answered here previously but I must not have used the proper search term. Help will be appreciated.
Thanks


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## Lehigh74 (Sep 25, 2015)

The best place to find info on clearances and track centers is NMRA. See NMRA RP-7 draft.

https://www.nmra.org/index-nmra-standards-and-recommended-practices

Most folks like to keep grades at or below 3%. You would be hard pressed to have 3% grades for an overpass with 5.75” clearance on a 5’ X 9' layout.


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## CTValleyRR (Jul 26, 2014)

I agree with lehigh -- grades are one of the things that get beginners into trouble. I'll assume he's looked up the vertical clearance in O scale and that's where the 5.75" comes from, and it's about what I would expect given the clearances required in HO. 

At a 3% grade, you need almost 16 linear feet to achieve that grade change, plus another 16 feet to go back down. That's more than one complete lap around your layout. And in practice, you need easements (short sections of shallower grade) coming on and off those steep sections, making the problem worse.

Also, the NMRA minimum separations are to allow trains to pass one another. There is no guarantee that a given structure or accessory will fit (although the turnout actuators should).


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## dindallas (Dec 12, 2016)

Thanks Lehigh74 and CTValleyRR for your responses,

Based on the information you provided, I will have to figure out if I can get enough elevation to allow an O22 switch motor to be positioned underneath an adjacent track. These switches are on outside of the layout so the switches can't be reversed. Roughly 2" elevation is easier to achieve than 5.75" elevation.

I will keep working on my layout in SCARM and on my platform. When I get one that will work, I will post it and ask for comments.

Thanks for your help.


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## CTValleyRR (Jul 26, 2014)

Any possibility of using an under the table switch machine?


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## dindallas (Dec 12, 2016)

CTValleyRR said:


> Any possibility of using an under the table switch machine?


I am using O22 switches. Where can I find information about these "under the table switch machines"?


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## CTValleyRR (Jul 26, 2014)

Personally, I use miniature servomotors from Tam Valley Depot (www.tamvalleydepot.com). Admittedly, I'm in HO scales, but I would think these would have plenty of "oomph" and travel to throw an O gauge turnout.


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