Double OO loop, running in different air temperatures

[8-Mile]

I'm planning a new build in a decent sized space above my garage. It'll be something like 18ft by 5ft, double loop. One 18ft wide half of the loop will be in the hobby room, nice and warm, and that's where all the points and scenery will be. The return loop (no points) would be the other side of an insulated dry wall in a dry space above the garage. Where I live the warm half of the loop would be around 20degC year round, and return loop could be (on a cold winters day) about -25degC and +38degC in the summer time. What should be I considering? I guess don't solder the rails in the cold side otherwise they'll buckle in the summer. Anything else?

[Dad-1]

Really only needing some planned expansion/contraction joints.
The art there is knowing what the temperature is when you're setting up.
Shouldn't need more than a finger nail thickness gaps.
One thing I'd be fussy over is EVERY piece of rail to have it's own power
feed off a bus.
Shouldn't effect running as the period spent in extreme cold is going to
be quite short.

Geoff T.

[centenary]

If you are planning any, Id also say be aware of your point motors in the side that's going to have a big temperature variation. If you're using something like DCC Concepts IP Digitals \ Analogs, Tortoise or just solenoids, their operating range might not like extreme cold \ heat.

If there are no point motors planned in that area, no problem!

[8-Mile]

I wondered a bit about air rushing into the tunnel, from hot side to cold side creating 'wind'. But yes, lot's of expansion joints. I also wondered about moisture... If the air inside the house is relatively moist (we use a humidifier in the winter because the air gets incredibly dry) and the warm air is going out that way then it might condense on the cold rails. There won't be any incline, but I don't suppose moisture is good for electrical connection.

[Bigmet]

But yes, lot's of expansion joints.

If this is nickel silver rail, a 1mm gap when the temperature is 20c wiil do the job

I wondered a bit about air rushing into the tunnel, from hot side to cold side creating 'wind'.... I also wondered about moisture... If the air inside the house is relatively moist (we use a humidifier in the winter because the air gets incredibly dry) and the warm air is going out that way then it might condense on the cold rails. There won't be any incline, but I don't suppose moisture is good for electrical connection.

The potential problem is that condensed moisture freezing onto the cold rails as frost, it's an effective insulator for small scale models such as HO and OO, based on my garden railway experience. If that became a problem, I'd think about putting 'trace heating' under the track, run at very low output. There will be suppliers local to you for this as it's a commonplace to protect industrial plant in a location like Michigan (well it certainly was in upstate NY near the lakeshore).

[8-Mile]

Hmm, interesting, I'm not familiar with trace heating but looking around there's certainly some inexpensive options. Will look into it, thanks!

sture freezing onto the cold rails as frost, it's an effective insulator for small scale models such as HO and OO, based on my garden railway experience. If that became a problem, I'd think about putting 'trace heating' under the track, run at very low output. There will be suppliers local to you for this as it's a commonplace to protect industrial plant in a location like Michigan (well it certainly was in upstate NY near the lakeshore).