track spacing to prevent buckling

[Decom]

I've seen on this forum that the recomended amount to leave space between track  when it's fixed down is approximately 1.5 mm, if this spacing is made for say The single straight (R600). Would i need to make spacing even larger for the longest straight piece (R603)? if so how would i account for this? I'd imagine if I just multiplied the 1.5 mm by the amount it was larger the gap would be too big for locos to use. Or is the 1.5 mm already very generous and it's enough space for the larger pieces?

 

the room it will be stored in isn't like a loft where it will get huge variations in temperature throughout the year because it's surrounded by heated and cooled rooms, but it hasent got heating or cooling for itself. so it's kind of half way between loft conditions and normal room conditions. 

[walkingthedog]

The same gap what ever track you use. 

[LCDR]

1.5 mm seems excessive, a third of that would seem to be more appropriate. My layout is in a garden shed where despite a small heater the temperature between summer and winter can be significant. I do not deliberately allow 0.5mm between the ends of rails laying my rails more or less by eye, but after five years I have not recorded any problem with excessive expansion. 

[walkingthedog]

A credid type card is about 0.7mm and that is the very most you will need. 

[96RAF]

Someone did the big sums on the forums a long time ago using the coefficient of expansion for nickel silver and from memory the neccessary gap wasn’t very big at all. What was significant was setting the correct gap relevant to the temperature at the time of installation, e.g. if it's very hot then little or no gap is required, but if its very cold then leave a significant gap to allow for expansion.

[SteveM6]

A gap about the thickness of a bank card will do, but lay track on a warm day when it has already expanded. It will open up when it cools down but there’s enough space to allow it to close up as it warms.

However lofts can get ferociously hot in summer so you may want to limit yourself to short lengths of track and therefore more gaps.

[Chrissaf]

I agree with the others......1.5mm is too big.

[Buz]

Hi Decom

Your gaps only need to be cigarette paper width.

So it just grabs the paper but doesn't tear it when you pull the paper out.

If you want larger gaps say a loft layout get adjusting tracks and inset them into the layout one each side of the oval evenly spaced you will have to run  jumpers around that to make sure you have power both sides of the adjusing tracks.

You could use Peco Expansion joints they actualy look like railway expansion joint so no need to hide them but same thing applied you need to jumper them.

regards John