The components of rail gunk (or “mung,” according to the current thread) seem to have changed over the years. One analysis in the 1960s found oil and grease, human skin cells and plastics used in railcar wheels. A new analysis mentioned in the thread discounts the presence of worn-away plastic and doesn’t mention household dust. “LkandO” sent a sample of dirty rail to a scientist friend for testing. Here’s what he reported: “The black crud is near 100% pure nickel oxide. Nickel (III) oxide to be specific. Saw the spectrograph output proving it. It is the natural oxidation of the nickel in the silver nickel plating on the track. Interestingly enough, it is deposited in such a manner as to suggest it was formed during an electrical arc. When viewed under extreme magnification it looks like random dots rather than a continuous film. “The metallurgist explained to me it is likely microscopic irregularities on the tread of locomotive wheels and track face and/or common dust on the track is causing momentary loss of electrical contact resulting in nanosecond duration, nanometer long electrical arcs which cause the nickel to oxidize far faster than would naturally occur. One could never see this with the naked eye they would be so small. He is only guessing based on observation of the deposits but who am I to question his analysis?
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“The oxide is also very tightly bound to the track. This explains why a Brite Boy is effective while wet wiping is not.” Thanks for having the analysis done, and for posting the results, LKandO! One thing we don’t know is whether the sample tested was used with plastic wheels, metal wheels, or a mixture of both. Many people have reported cleaner track and better conductivity after discarding plastic wheels and installing metal. At any rate, the report set off a wave of discussion and suggestions. MRH Pooh-bah Joe Fugate, who has done his own investigations into arcing and rail crud, suggests using mineral spirits as a rail cleaner, because it will leave a slight film on the rail that inhibits electrical arcs. Joe says the mineral spirits don’t significantly reduce tractive effort. He suggests shutting off of the layout lights and watching a running train in the dark to see how much arcing happens.
Page 18 • Mar 2012 MRH MRH Questions, Answers, and Tips, page 4
As for rail treatments, Wahl Clipper Oil has a lot of supporters. Other people report success with No-Ox, CRC Contact Cleaner, and with 2B graphite sticks (sold at art supply stores).
at Alan’s LK&O website, at www.lkorailroad.com. — MRH
A couple of principles emerge: Protect the rails from dust and dirt. Scratchy products like Bright Boys and emery boards are good for cleaning away paint, plaster and heavy dirt deposits but leave rough spots that collect more crud. Occasionally applying some sort of treatment can extend the interval between cleanings. Cleaning track is pointless unless wheels on rolling stock are also clean. Railroads that run trains frequently have fewer problems with dirty rail than railroads that rarely run. Say that five times fast. If all of the discussion in the thread has your head spinning, take a break
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