If you have rust likely you have humidity in your basement. I recommend getting a humidity gauge (they are cheap enough) and seeing what it is. If you live in a place with high outside humidity your basement can end up becoming very humid. Anything above 50% is really suspect, I would try for 40-45.
And yes, the plating does matter. I have a problem with rust on Ross track I have, and Steve told me that they had a batch batch when they were forced to shift platers (his old supplier was knocked out by a fire I believe). On my rail it was weird, it was the center rail that got it, the outer rails were fine. On the other hand I did have high humidity, my old dehumidifier died, I have an ac unit down there and I thought it would suffice...it didn't, and this year was especially humid, it was like the gulf coast of Florida in summer.
With tinplate track, I would use a sanding block or fine grit wet/dry sandpaper (I have used 800) to clear the rust from the top of the rails. By doing that, you won't removed much of the plating, a rougher paper would.Others have suggested using vinegar on a rag, I haven't tried that.
The biggest thing though is again get a humidity gauge, and see what you have. It could be it is fine today, but in the heat of summer it could be really bad, it is a worthwhile investment (you can get them really cheap, less than 10 bucks). Even if it looks dry today, it could be bad in the future. The weather is definitely changing, could be you were once fine and now are getting higher humidity weather regularly.
