Sulfur is a red herring; the problem is with real silver, not nickel “silver”, and it has long since ceased to be a major issue in many respects.
In the bad old days when high-sulfur coal and fuel oil were dominant fuels, the days of acid rain, the sulfur dioxide in room air could be high enough that table silver would blacken in a matter of weeks, and everyone had a can of Wright’s and a bottle of Tarn-X so that any time you actually wanted to eat without that awful taste you could polish up your place settings and stuff.
Then coal went out as a fuel, you could actually see farther south than 72nd St. from the George Washington Bridge, and the tarnish rate slowed down.
More recently, the big push to ULSD reduced atmospheric sulfur content still further.
If there is any question that sulfiding is some kind of issue, just get a bottle of Tarn-X and wipe some along the railheads per label directions.
I was careful to point out that the sulfur reference came from the Internet. I have no idea.
All domestically supplied natural gas has sulfur in it, even if it’s just the mercaptan component. Mind you anyone cutting onions in their kitchen is loading a bunch of sulfur into the air. Boiling cabbage?
I noted a long time ago that natural rubber (such as found in socks or waistbands for example, or rubber bands) deteriorated when stored in our furnace room. Natural gas furnace and water heater. The same thing happened after we added a furnace to our detached garage. I assumed it was from the ozone from the electric motors. Maybe not? Fitting a more modern furnace has reduced the effect and newer furnaces use brushless motors as far as I know so a lot less ozone emitted from those, maybe none.
At any rate, in my limited experience (2 years now) of running trains the best way to keep rails cleaner is to run trains more frequently. Sounds like fun to me, more fun than rubbing whatever over the rails instead. A simple track cleaning car such as the one Bachmann makes, also seems simple enough to use now and again and more fun than rubbing the rails.
Track fiddler
Because of the poor continuity between the wheels of our locomotives and the rails, what happens is nano arcs are created every millisecond the continuity is broke. Basically the exact same thing as arc welding only on a microscopic scale. These nano arcs create microscopic pits in both the rails and the wheels of our locomotives. The more it happens the more the byproduct of this builds on our tracks until you clean it again.
[Note: the Optical-Apparatus Induced Translucency Induction Alliance WG13 guidelines suggest a MEGO warning be appended to the following reading material]
To add a little here: air breaks down to plasma at electric field strengths that are very high per centimeter… but there are very few centimeters in track irregularities that momentarily interrupt conduction, vs. the inductance represented by, say, motor windings that increase current as such interruptions and re-establishments occur.
This is where the longitudinal scratching from Bright Boys and the like comes in. In addition to the nominal ‘line’ contact between a roughly-cylindrical wheeltread and longitudinal railhead, the transverse contact area then becomes more restricted to the ‘points of the (normally longitudinal) scratch ridges’, which also poke up out of any oil or other ‘insulating’ material (don’t bring up that ‘conductive lube’ again, as we know none of the popular ones in model railroading literally are) but are not consistent. If there is any ‘chatter’ in the scratch-ridge formation, or the heights are irregular, you’re setting up for en masse make-and-break over time.