Track gap

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Posts: 11
Joined: Sun Mar 07, 2021 12:08 pm
Location: Carlsbad, New Mexico, USA

Track gap

Post by Quacker »

It has been 60 years since my last layout and many things have changed. I am sure I will have many questions as time goes by.

I live on a ranch in the southeast corner of New Mexico where the summer temperature of 100 degrees (F) is very common and usually at least once a summer the temperature will reach 115 to 118 degrees (F).

I am in the designing stage and the layout will be in an unheated, uncooled outer building. I will be working with N scale, 36-inch flex track. I am concerned about rail expansions of the rail due to heat.

My question is: How much gap at rail joints should I have?

FYI When it is 100+ degree (F) I will not be in a non-air-conditioned building! :)

Thanks for the help
Ms. Jackie

I just did a test to find what the gap should be.
Track N gauge 80 Flex track
Start length 36 1/16 inch test length 36 1/8 inch Difference about 1/16 inch or 2MM
Start Temperature 80 degrees (F) Test Temperature 119 degree (F)

I performed the test by removing one rail from the track. I marked the length of the rail on a piece of brown paper. The rail was left in the sun for about 2 hours. When the temperature Reached 119 degrees (F), using an inferred thermometer, I made the measurement.
Last edited by Quacker on Wed Mar 10, 2021 7:03 pm, edited 1 time in total.
Posts: 27
Joined: Sat Mar 06, 2021 9:28 am

Re: Track gap

Post by bsuarez »

Great question Ms. Jackie

Too much gap and you run the risk of derailments and not enough could causing buckling or distortion. That being I said I would go with no more than an 1/16" gap and stagger the joints so you don't have both rails joining across from each other.

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Joined: Mon Mar 15, 2021 6:32 am

Re: Track gap

Post by Drainbrain »

How about letting the track float at certain areas that will absorb the expansion.
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Joined: Fri Mar 12, 2021 7:38 am

Re: Track gap

Post by SealionSteve »

Ah, I see now why you were asking about cutting right through the rails in the separate thread under "Track". Here in Lincolnshire, UK we call 70 degrees a hot day!

I'd suggest doing alternate "nicks" in the surface and cuts right through, with the type of cut staggered in the opposite rail so you don't have complete gaps opposite, except where one length of track joins another.

You'll obviously need to have separate power feeds somewhere in each section of track.

Have posted a similar response in the "Track/Flex track" thread.


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