# Track Troubles



## Redrider (Apr 19, 2017)

I want to buy some track but all I am familiar with is tubular O27 from a 1973 train set. I have discovered that O27 is too narrow a turn for some Locomotives and Rolling Stock. I want to be able to use an SD70ACE or similar type locomotive some day, but if I build my track incorrectly, it will just be a shelf trophy.

I need to understand how many curves are needed to build a standard oval set up. Is there a formula I can use? 8 O27 curves build an oval, I just put one together for my grandson. But if I have to use O54 or O72 for a bigger locomotive, I need to know how sweeping a turn I am faced with. Any help or information is greatly appreciated.

Redrider (john)


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## highvoltage (Apr 6, 2014)

The number tells you the diameter, O54 is 54 inches, O72=72 inches, etc.

The number of segments in a curve differs. Here is a link that explains it:

https://support.modeltrainstuff.com...pieces-of-track-do-you-need-to-make-a-circle-


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## Lehigh74 (Sep 25, 2015)

The minimum diameter for any locomotive (or rolling stock) is usually stated on the manufacturers website. MTH Railking will run on O31. For MTH Premier the minimum diameter can range from O31 to O72.

In addition to the link that high voltage posted, here are a few for Ross and Gargraves.

http://www.rossswitches.com/rcspricesheet.pdf

http://www.gargraves.com/sectionaltrack.html


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