I was laying some track tonight when I noticed a piece of Atlas code 83 Flex track had turned color. About the last 3" on one section has turned a orangish yellow and bluish green. Can anyone tell me what it is and why it happened? I am able to rub the blue green part off with my fingernail but the orange yellow takes a bit more. All the rest of my track looks fine and it’s all been sitting on the layout, why just this one spot on this one piece?
Thanks,
Aaron
Call CSI.[:-^]
You didn’t happen to put soldering flux on that piece and forget about it?
loathar… it’s possible I could have. If I did it would have only been on one rail. Both rails are affected.
My track does it too. I don’t belive its an issue I just clean it up with a bright boy and train traffic is uneffected
Hi Aaron: I have 5 code 100 Atlas Custom Line switches with the same discoloration. They are some of the last Atlas switches I purchased. It doesn’t seem to affect operation, so I’m not worrying about it. Here’s a pic. 
That is actually a tarnishing of the metal used in the rails and is caused by a bad connection when plated . They are not defective and when they are soaked in a chemical cleaner the tarnish goes away for a period of time and as moisture is around they slowly begin to tarnish, I beleive they are plated with either a nickel or tin based plating solution, and after a long period of time they may need to be recleaned as far as the inside and top rails are concerned.
Plated with what? Last time I checked, the rail was solid, homogenious metal. At least, the rail drawn by Cactus Brass for Shinohara was (and presumably still is.) So, was the rail drawn in China (where quality control is a dirty word) or somewhere else. Either way, was the lubricant used in the drawing process completely removed? If not, that might be the culprit.
Chuck (modeling Central Japan in September, 1964)
It’s a conspiracy![alien]
Nope. I talked to Atlas. Their rails are solid NS. Not plated.