# Black dust on the track.



## Old Bandit (Mar 5, 2013)

I run a little indoor layout (5' x 8').
I use the Piko G-track (pure brass alloy).
But, after one or two hours, I find a black dust on the track.
If anyone knows what's going on here, thanks for your help !


----------



## Dave Meashey (Jan 2, 2008)

Bandit; 

Do your cars have plastic or metal wheels? Some plastic wheels tend to leave a black residue on the track. Many of us who have been in the hobby for some time tend to replace the plastic wheels on a car with metal wheels before ever running that car. 

There will always be some dust that will be ground onto the rail heads by your equipment - indoors or out. What kind of heat/AC do you have? Forced air systems tend to circulate loose dust more, despite filtration. Do you have a smart thermostat that tells you when to change air filters? If not, you may want to check your filters. 

Not all the answers, but a few that come to mind. I'm sure other members wil offer other good suggestions. 

Best wishes, 
David Meashey


----------



## Totalwrecker (Feb 26, 2009)

Ssshhhhhsssssssss He's back! Kinda reminds me of me when I was burning bridges in front of me! 

My 0-4-0 with the old wheels, arced alot snd left a black reside. Aristocraft offered replacements way back when. 

Happy Rails 

John


----------



## Totalwrecker (Feb 26, 2009)

What, may I ask, is 'Pure Brass Alloy'? If it's an alloy it's not pure anything, by admission. A 'virgin' brass alloy, I'd take as a good thing. 

Lost in translation? 

Struck my funny bone and gave me a giggle. 

John


----------



## Greg Elmassian (Jan 3, 2008)

'Pure Brass Alloy' is by definition an oxymoron.









If you are using metal wheels, at least on your locomotive AND you are using track power, this is carbon dust, caused by the normal arcing from power conduction between the wheels and rails. No getting around it. 

Plastic wheels tend in my experience, to leave a hard residue on the rails, while the carbon dust can be wiped up with a finger. 

Greg


----------



## Ted Doskaris (Oct 7, 2008)

For track power,
When rail head surfaces, rail joiners and / or loco wheel treads are dirty, pitted (or if wheel plating wears away) can result in excessive electrical arcing and black carbon and / or copper oxide deposits forming under the rail joints, on rail head surfaces and wheel tread surfaces. It's degenerative and feeds on itself getting worse and worse until intermittent operation results.

Using plastic wheels on the cars makes the problem worse by contributing added residue mixing with the deposits making for an insulating goo.





























Wheel tread surfaces and track rail heads must be cleaned periodically.

-Ted


----------



## chuck n (Jan 2, 2008)

If it is metal wheels on brass track, I do not see where the carbon is coming from. I have always thought that the "black dust" was fine, dust, particles of brass that the harder metal wheels ground off the top and inside edge of the rail. Many metals when ground fine enough yield a black powder. My biggest problem with arcing wheels is on my LGB mallets and the Zillertal Bahn tank engine. These do not have sliders and all current come in through the wheels. This is rarely a problem with other manufacturers who do not have sliders; Accucraft, Aristocraft, and Bachmann.


Chuck


----------



## Greg Elmassian (Jan 3, 2008)

Carbon is caused from arcing. Ever notice the black carbon dust when you short wires together that have significant voltage or current? 

The carbon comes from the electrical arc through air I believe. 

When I first started, could not figure out where it came from, then looked carefully at the wheels sparking to the rails at night... 

Trust me, ground off brass looks like brass, ask anyone who has a commercial display layout with brass track... 

Also, it is my belief that different metals have different "arcing" amounts... stainless seems to be the worst. 

Greg


----------



## chuck n (Jan 2, 2008)

Greg:


The chemistry doesn't make sense to me. The carbon in the atmosphere is already oxidized to CO2. In order for it to be elemental carbon you would have to reduce it in the high temperature of the arc in the presence of abundant oxygen. My best guess is that the black you get when you touch two hot wires is copper and other metal oxides coming from the wires. 


Chuck

The concentration of *carbon dioxide (CO2) in Earth's atmosphere* has reached 391 ppm (parts per million) as of October 2012 (from Wikipedia). That is not very much.

Copper oxide (CuO) is a black powder.


----------



## Old Bandit (Mar 5, 2013)

Gentlemen, thanks for your help !

I use metal wheels and track power (DC/21 volts).
I don't have heater or AC in my garage.
I clean wheel tread surfaces and track rail heads periodically.

Thanks for your many answers.


----------



## Greg Elmassian (Jan 3, 2008)

Chuck, please research arcing causing carbon dust.... then you will satisfy yourself... Note well my words: "The carbon comes from the electrical arc through air I *believe*. " The chemistry itself does not really interest me. I spent years fighting this stuff and did not realize where it was coming from until Ted and I got our heads together... I believe he was the person who helped me put the pieces together.

On the main topic, what is the dust, well, I guess you have never shorted some wires together and seen the carbon around it, or around a wall outlet when the plug shorts, or carbon tracks inside a distributor?

I can guarantee you that the small sparks between the wheels and the rail is causing the carbon... I had squeaky clean wheels and rails and a bit of running made the powder.

I have seen it in ALL scales I have modeled... HO, G, N, Z .... I just never realized until I really scrubbed my outside loop of stainless and it got this black stuff and I knew for sure there were no other contaminants there... running a loco ONLY with stainless wheels ...

Anyway, I've given you all the information I can and won't argue the point further.

Greg


----------



## BigRedOne (Dec 13, 2012)

I seem to get a slimey or sticky black buildup, too. 

When I had this problem in Marklin I assumed it was the black rubber traction tires wearing, but the LGB tires are a yellowish color. I see a light gold coating developing around the flanges of the wheels, suggesting that brass is wearing off the track as well.


----------



## Totalwrecker (Feb 26, 2009)

Regarding the fine particles of metal going black, it's a very fine particle, the size you get when you rub your finger on the metal and your finger goes black. 
I know from black fingers that it is true for silver, gold, copper, brass,nickle aluminium etc.... 
I was told by a college teacher that it is true for all metals. 

Not being fine enough is not a valid arguement.... but hey, that's just the facts.... 

John 
a retired Gold and Silver smith.


----------



## chuck n (Jan 2, 2008)

Not to beat a dead horse, but there is abundant carbon in the vicinity of both of your examples, insulation in the case of the wires and plastic is all around the plug. When I get back home I'll try to analyze the black dust. Chuck


----------



## chuck n (Jan 2, 2008)

Another dead horse. This happens all the time, whether there is arcing or not. Stan Cedarleaf has a tight loop that he runs all day almost every day. I think that it is an LGB R1. If I am wrong I am sure he will correct me. He has mentioned that he has to replace the track every so often because the inside of the outside rail has worn away. I stand by my original hypothesis that the black dust is a very fine powder of brass. I hope that I can convince some of the chemists at my former employer to help with the analysis. Chuck


----------



## Greg Elmassian (Jan 3, 2008)

So what is the fine dust on my stainless steel rail? Bits of stainless worn off? In one hour of running? Ground so fine that there is no abrasive quality to it? No way.


----------



## Totalwrecker (Feb 26, 2009)

Like Greg I got it on stainless. 
Noticable after a couple of laps.... 
Mine was from arcing, batteries cured it. 

John


----------



## chuck n (Jan 2, 2008)

How do you know that the dust isn't abrasive? In my lab I used 1 micron diamond polishing paste as a final polish. You could rub something all day with it and without mechanical help you couldn't see a difference. Are your trucks arcing all the time? Knowing your care of your trains I doubt that the wheels are dirty and there any significant arcing. Chuck 

John has a second answer, that makes sense, II'll bow out.


----------



## Greg Elmassian (Jan 3, 2008)

What I am saying, I have clean rails, clean stainless wheels, and in one hour running it grinds off bits of stainless steel, but somehow they turn black, and are ground so fine that you cannot feel any significant abrasive qualities? 

Nope, carbon buildup from arcing, and stainless wheels arc more... have actually tested and observed this... also backed up by my friends trying the same thing... 

Also if this is abrasion, why isn't there more on the curves and less on the straights? Why isn't there more on the outside rail than the inside? 

carbon from arcing.... read up on it...


----------



## Old Bandit (Mar 5, 2013)

Congratulations Gentlemen !
























I really know what's goin' on.

Thanks for your help !


----------



## jake3404 (Dec 3, 2010)

I dont care what it is, but its there. I dealt with the oxidation on all my HO layouts. It is the main reason I chose to go battery on my outdoor layout. I wsa told once that if you run your trains more often, then the oxidation tends to not buildup as much. I never tested that theory. I use a CMX car on my HO layout the first round or two on the back of a train on my HO layout and that does the trick.


----------



## backyardRR (Aug 14, 2012)

Where I live (NYC suburb with much traffic) I have always noticed a slight accumulation of black "soot" on most outdoor surfaces. Probably from automobiles and trucks. The rain washes much of it away. God knows what our lungs are breathing in. This past year my patio based garden railroad test loop still stayed fairly clean despite this crud. A quick pass with the Scotch Bright does the trick. It will be interesting to see how the actual permanent RR handles this. I really need to get a track cleaning car. Just saying.....
Wayne
Knackered Valley Railroad
Long Island, NY


----------

