# Track expansion



## Big Ed (Jun 16, 2009)

I got a PM from buccsfan64, Will an expert N scale man tell him why and a fix? Heat and cold would do that. I never laid any N scale track yet. 
My little layout I got given to me.

His question,


*track expansion* 
Hi Ed, is see you are a train master so hope you can help me. Im building a 4x8 in N scale. So far i have put down two outer tracks with switches between inner and outer. they run pretty much the perimeter with 19 inch radius. I have this in my garage and when i checked it yesterday some of the track near the switches had shifted. I have the track glued to foam roadbed and it's mostly flextrack. Is the shift caused by thermal expansion of the track in the heat? If so, whats the best way to combat this? I soldered the joins so I was thinking unsoldering a few locations and having expansion room in the connectors. Thanks, Robert


----------



## shaygetz (Sep 23, 2007)

The rail gets metallurgical stresses built into it thru the rolling process that makes the rail. When you get new flex track, you need to do one of two things to it...hook up track power to it for a couple minutes or flex it back and forth in your hands---no kidding. This relieves the stresses that cause the kinking that appears when you power up new track.


----------



## Big Ed (Jun 16, 2009)

shaygetz said:


> The rail gets metallurgical stresses built into it thru the rolling process that makes the rail. When you get new flex track, you need to do one of two things to it...hook up track power to it for a couple minutes or flex it back and forth in your hands---no kidding. This relieves the stresses that cause the kinking that appears when you power up new track.



I never heard of that, sounds logical. But a damp or humid condition affects the rail too. 
I have yet to glue any track down or worked with flex track.
Thanks Shaygetz.


----------



## NIMT (Jan 6, 2011)

When I built my last layout in Phoenix I had the same situation pop up before I put in expansion joints. It was 45 deg when I layed the track and a couple months later when it hit 120+ in the shop all the track when all over the place, 4 sections of expansion joints did the trick and my mains were about 70 feet long.


----------



## Carl (Feb 19, 2012)

Always, make a small (narrow) cut thru the track for expansion & contraction. I do not wish to sound demanding but the track does move due to heat and cold (common problem with metal).


----------



## buccsfan64 (Jan 22, 2012)

Thanks everyone, thats what I was thinking. I'll allow a few areas of expansion in the straightaways, the radius areas seem ok for now but i'll keep an eye on them. I laid them down in a cold garage and it was probably 110 in there yesterday. I'll calculate the expansion of nickle and add just enough. I dont want huge gaps in the winter..


----------



## T-Man (May 16, 2008)

A while back I did a quick brass rail problem, Here.

Brass would be more than nickel in expansion.

Here is the info

I checked on the linear expansion of Metals. They are around 6, brass is just over ten and aluminum is 12.

The units are micro inch/inch per degree F. So brass is 1.0 to the minus 5th inches per inch per degree F. So 100 inches of track at ten degree change, will be 100th of an inch.


----------

