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Hi

Good question about when do you fit the expando rail.  I hadn't thought of this before but here is my reasoning....

I would see if you can work out the difference in the length at high and low temps - this should give you an idea of the amount of expansion you are dealing with.  If the expansion is more than the "give" of the expansion rail, you probably need more expansion sections.  I don't know the expansion/contraction rates of the material in your track, we could work it out (50 ft x expansion rate due to heat).  The bowing would also be related to the temp. when you layed the track out in the first place but not much you can do about that now.

Assuming you don't have that much expansion and only need one expansion section, you could try one of three options:

1) Fit it when the rail is at its hottest, with the expansion rail near (but not at) its minimum.  As the rail cools, it should extend the expansion rail as the rest of the rail contracts.  I wouldn't set it at the minimum, as you may well have a hotter day (global warming /DesktopModules/NTForums/themes/mls/emoticons/sad.gif  or just bad choice of "hot" day). 
2) Fit it on a very cold day with the expansion nearly at a maximum. 
3) Pick an average day with the expansion rail set in the middle of its expansion capacity

OK - so that probably didn't help very much, but with all the really helpful and experienced people in this forum, I am they will be able to see the flaw in my logic and correct me!

regards

anthony
 
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