I remember seeing this a few years back. I briefly considered switching lubricants, but then I considered that this test is conducted at 100 degrees Celsius - the boiling point of water. I don't know about you, but I can't remember picking up up a loco and finding the gearbox hot to the touch, let alone boiling. Granted, I don't run them for hours at a time. Anyway, I would be surprised to see corrosion in my lifetime - the conditions we use our trains under are child's play compared to what this product is designed for.
I have not been able to locate ASTM D130 copper strip corrosion test results for Red 'n' Tacky. At the time, I considered switching to Super Lube, which scored very well (1b) on that test, but I didn't like that it contained PTFE (Teflon). If high pressure additives in Red 'n' Tacky can possibly seep into oilite bearings and plug them, PTFE is far worse. In fact, Super Lube's literature says that the PFTE is designed to come out of solution and coat the gears... I didn't want that stuff near bearings. If they have a no-teflon product, I might yet switch to that...but I already have a whole tube of RnT 
And I'm just not convinced it's that big a problem.
So I've stuck with Red 'n' Tacky. It stays where I put it. It doesn't harden. And everything I use it on runs like silk.
