Does heat/humidity effect fastrack?

 Don't no but it will rust  have seen the rust on it in a layout at train store

I had about 350 feet of Fastrack for years.  Heat and humidity within limits (up to 100% hum and maybe 45 - 95 temp) did not seem to affect it at all. 

I think it it rusts, its because you did something stupid, like clean it with sandpaper or steelwoold - or Simple Green!

Well i seen the rusty fastrack at the store so i got real trax

Never had a problem with lots of it. I did buy a 2 cases of straight   one time and a two bad ones out of 100. No other problems.

No oxidation on my Fastrack so far in my basement for the last 6+ years!  The temperature fluctuates from 59 to 75 degrees, but I keep the humidity around 45 percent with a dehumidifier which is about 10 feet away from the layout.  Near the layout, the humidity is usually between 45 - 50%, drier if mother nature wants.