# Question regarding real train wheels



## xrunner (Jul 29, 2011)

Was reading an article in the current Model Railroader (May 2012) about N scale wheels and was curious about this -



> "It's good that metal wheels have shiny treads. But the rest should be brown, as prototype wheels rapidly oxidize to that color. (It's against federal regulations to paint a wheel)."
> 
> Model Railroader, May 2012, p. 20


Why is there a regulation against painting real train wheels? What is the reason for that?


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## sawgunner (Mar 3, 2012)

wow that's a weird one! who woulda thunk that painting a axel wheelvset would be a bad thing?

could have sworn i've seen them painted before going down the rails


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## Gansett (Apr 8, 2011)

I'm just going to guess that paint might cover and hide cracks that could lead to wheel failure.
Chrome plated wheels weren't allowed in Nascar for that reason for a long time.


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## Carl (Feb 19, 2012)

Sounds like something the pencil pushers in Washington D.C. might dream up, Might find something about it at this link:

http://www.transalert.com/bookstore/Rail/Government_Regs/?gclid=CKfnh-u6nK8CFWHptgodvkKecw

Have fun trying to understand the regs.


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## rogruth (Mar 6, 2012)

If I remember correctly the hiding of faults is the reason.If you will notice on a real train the couplers and some other small items are not painted for the same reason.


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## xrunner (Jul 29, 2011)

rogruth said:


> If I remember correctly the hiding of faults is the reason.If you will notice on a real train the couplers and some other small items are not painted for the same reason.


The wheels oxidize (rust) without paint as we all know. Also, I understand that paint could also cover up cracks. So my question would then be - why not paint the wheels with a clear coat? That way, you would prevent corrosion and also be able to see cracks.


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## Brakeman Jake (Mar 8, 2009)

I've spent my working life repairing heavy machineries and I can tell that indeed paint can hide microscopic cracks in wheels,hubs,etc.Many times,cracks are so small that even on unpainted items,they are nearly invisible to the naked eye.However,even very small cracks tend to develop into a hair sized rusty line and/or have the surface dust show the said crack...clean the item...crack disappears.Paint changes all this so no,it's not a nonsense rule....


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## New Berlin RR (Feb 11, 2012)

its the whole thing about safety that is going on here honestly...nuff said  paint means cracks could be hidden...and yes it makes sense to me honestly as far as thats concerned...


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## xrunner (Jul 29, 2011)

Brakeman Jake said:


> I've spent my working life repairing heavy machineries and I can tell that indeed paint can hide microscopic cracks in wheels,hubs,etc.Many times,cracks are so small that even on unpainted items,they are nearly invisible to the naked eye.However,even very small cracks tend to develop into a hair sized rusty line and/or have the surface dust show the said crack...clean the item...crack disappears.Paint changes all this so no,it's not a nonsense rule....





New Berlin RR said:


> its the whole thing about safety that is going on here honestly...nuff said  paint means cracks could be hidden...and yes it makes sense to me honestly as far as thats concerned...


No, not "nuff said" gentlemen.

1st point - If your logic is right, then why paint anything having to do with safety and people - why paint aircraft, bridges, buildings, boats, busses, etc.. I mean, according to you all the cracks will be hidden!

Second point - if they are invisible or nearly so, then corrosion and dirt will obscure them anyway without cleaning and there is equipment available that can find them even if they were painted or obscured.

Your explanation is lacking.


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## Brakeman Jake (Mar 8, 2009)

You're right,paint has its purpose outside improving the looks...it preserves equipment.And a normal coat of paint will not hide cracks either,so no argument there I agree.

But,during my forty year career,I've seen a couple cases where truck wheels did indeed have very small cracks...when showed to the customer the answer was "well,they're not important cracks (read "expensive" between the lines) and the requested solution was to put a heavy coat of paint on the wheel.The obvious purpose was to hide them to the road inspectors.

A failing train wheel may have such devastating results so even the smallest crack calls for a wheel replacement (with the costs and down time).I don't think that major railway companies would gamble on this but what about smaller privately owned companies?Since the governments can't have specific rules for every railway nor controlling paint thickness,the simplest rule is no paint for every one.

If everybody was thinking "safety before profit" instead of the other way around,stiff rules and implementations wouldn't be required.Unfortunately,"real life" shows different.And you've probably noticed,this rule applies only to highly critically stressed components like wheels for instance.


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## sstlaure (Oct 12, 2010)

Roll cages in off-road vehicles (SCORE, etc) don't have their cages painted either so that they can be inspected (typically a florescent penetrant is used) I would think RR companies would have similar Preventative Maintenance schedules/inspections that would need to be performed every so often requiring the surface to be paint free.


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## Gansett (Apr 8, 2011)

That's interesting Scott,
Our cages and interiors were required to be painted. Our cages/frames etc were inspected prior to paint at the shop and again pre season at the track using a sonic whatchamacallit thingy.


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## Reckers (Oct 11, 2009)

It's my understanding that, on steamers, it was often the practice to paint the tires on the drive wheels. The reason was that it made a thinning tire apparent to the maintenance people, as well as a badly worn spot on a tire from a screeching stop.

And for those who might be confused by tires on a train, steamers had huge, cast-iron wheels which would wear poorly against steel rails. To protect the wheels, a steel rim, or tire, was mounted around the circumference of the drive wheel and could be replaced as needed. It's the same sort of rim you'd see on old, wooden wagon wheels.


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## bwoogie (Mar 31, 2012)

Why would you paint the wheels anyways? Metal on Metal its gonna wear off in 3 rotations am i right?


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## xrunner (Jul 29, 2011)

bwoogie said:


> Why would you paint the wheels anyways? Metal on Metal its gonna wear off in 3 rotations am i right?


Only the metal that contacts the rails. The rest of the wheel rusts and rust is bad for metal. If you want to see cracks just clear coat it.

If you don't believe painting metal is good and that it leaving it unpainted enables cracks to be seen better, then please explain why aircraft metal is painted (or clear-coated).

Many thanks.


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## Xnats (Dec 5, 2010)

I personally thinks Jake's explanation is pretty feasible. Applying some sort of application to prevent corrosion is a brilliant idea, but. What is being left out is, Federal Employees are making these calls. Most of the higher positions/ titles that are making the calls don't really know. They got to this point from knowing someone, transferring from another area for a promotion or just having some much tenure as a Civil Servant, they have no common sense left and there is no place left to put them but on top. Remember a civil servant is promoted by taking general knowledge test, not by being good at their specific skill or trade.


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## Gansett (Apr 8, 2011)

X,
After WWII and prior to VietNam the military had gotten away from painting aircraft, then at the onset of VN they were again painted, solely as a means of camouflage. The "insides" of a aircraft are painted with a light coat of zinc chromate primer as a corrosion inhibitor. We've since stayed with the camo paint. Some aircraft are painted with a special radar absorbing paint, the SR-71 is a prime example.
Commercial aircraft are painted as advertisment for the airline. General aviation solely as a matter of asthetics. Under the color coats is a coat of zinc chromate primer again as a corrosion inhibitor. I've never seen a a/c that was clear coated, not so say some aren't. Paints used since the 70's are urathane based single stage systems.
4 years USAF as Airframe repair, 2+ years with a commercial airline.


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## xrunner (Jul 29, 2011)

JackC said:


> Commercial aircraft are painted as advertisment for the airline. General aviation solely as a matter of asthetics. Under the color coats is a coat of zinc chromate primer again as a corrosion inhibitor.


We've got a few tangents going on here. Focus on one.

Are you stating for the record that aircraft do not need to be painted? That raw aluminum is OK to be left to the elements without paint of any kind JackC? Seriously?


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## Xnats (Dec 5, 2010)

What is wrong with aluminum being left in it's natural state after manufacturing. Body panels are most likely only painted for cosmetic reasons, no one would not want to fly on a weathered looking plane. I bet lunch the frame is left untouched. You also can not compare the two metals aluminum and steel. What grades are you comparing between the two. Natural aluminum left to the elements are traffic signal pole, lighting poles, conduit secured to galvanized plated steel.
Lets go back to the train wheel. What is the life expectancy of the wheel, 5 yrs, 10 yrs? What grade of steel is it? How much heat is produced when rolling on a steel track? How much heat would be trapped if you painted the wheels? How much would it's service life be shortened doing so? Why are tracks not painted? Could it be for it's expected service life it would not be economical to apply a paint system to protect it and provide maintenance. Some steels/ grades are designed to flash rust which servers as a protective coating. Look at guide rail and over head structure in Federal Parks and major toll roads. They are bare steel left to flash rust brown, to blend into the environment.


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## xrunner (Jul 29, 2011)

Xnats said:


> What is wrong with aluminum being left in it's natural state after manufacturing. Body panels are most likely only painted for cosmetic reasons, no one would not want to fly on a weathered looking plane. I bet lunch the frame is left untouched.


The frame is not left untouched. I used to work in a lab next to a fighter jet manufacturing line and the internal frame is painted with a greenish/yellowish primer. And of course the outside is also painted.



> You also can not compare the two metals aluminum and steel.


Yes I know - we have other machines entering the conversation that's why I was talking about aluminum.



> What grades are you comparing between the two. Natural aluminum left to the elements are traffic signal pole, lighting poles, conduit secured to galvanized plated steel.


I know, let's get back to steel ...



> Lets go back to the train wheel. What is the life expectancy of the wheel, 5 yrs, 10 yrs? What grade of steel is it? How much heat is produced when rolling on a steel track? How much heat would be trapped if you painted the wheels? How much would it's service life be shortened doing so? Why are tracks not painted? Could it be for it's expected service life it would not be economical to apply a paint system to protect it and provide maintenance. Some steels/ grades are designed to flash rust which servers as a protective coating. Look at guide rail and over head structure in Federal Parks and major toll roads. They are bare steel left to flash rust brown, to blend into the environment.


I don't know the answers, that's why I asked the question. No one has given an answer yet based on a quote from a document that explains _why_ they aren't painted. You've given your opinions but that's all. All I've seen is the quote from the magazine stating they aren't painted. I can't find the answer yet on the internet. But I do know that steel bridges are painted and also steel parts all over the place because, because, because ... steel rusts and rust is not good for steel parts. Do you disagree that rust is a bad thing? I mean, let's just leave steel bridges unpainted so we can find the cracks easier. Hmmm - something is not right with that idea.


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## Gansett (Apr 8, 2011)

xrunner said:


> Are you stating for the record that aircraft do not need to be painted? That raw aluminum is OK to be left to the elements without paint of any kind JackC? Seriously?


Yes. Aluminum sheets have been processed and are All-Clad with a thin coating of pure aluminum. That's why when doing repairs it's important to not have a oopys and scratch the exposed surfaces.
From Boeing:
note what determines paint v polish. "The decision to paint or polish the metal surfaces of airplanes is based on marketing, economic, and environmental considerations." 


http://www.boeing.com/commercial/aeromagazine/aero_05/textonly/fo01txt.html


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## Xnats (Dec 5, 2010)

lol ok. I was getting worried. A good debate can turn into an argument fast trying to compare parts, materials and components designed and used for commercial applications to standards and specifications of the US Military. :laugh:

Try searching "patents for steel railroad wheels" The first hit I had was this. 
http://www.freepatentsonline.com/5333926.html
It goes over the forces involved in the design. I started reading but the family is waiting, lol. 
On the note of bridges. It the grade of steel and the requirement of it to be painted. Yes it would rust out without a protective coating system. The iron to carbon ratios are different. This is beyond me though. That is why I mentioned guide rail and sign structures which are designed to flash rust and serve as the protective coating system. More research would have to be done of the steels involved in each application.


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## gunrunnerjohn (Nov 10, 2010)

xrunner said:


> Are you stating for the record that aircraft do not need to be painted? That raw aluminum is OK to be left to the elements without paint of any kind JackC? Seriously?


Yep, seriously. A number of aircraft are totally unpainted. I remember some rather ancient aluminum aircraft that were virgin aluminum and lasted very well. Here's even a cleaner specifically mentioning unpainted aluminum aircraft components: Cleaner for Aircraft Components, Cold Tank Type, Solvent-Base

American Airlines has a lot of unpainted planes, they polish the aluminum to keep it looking nice.


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## plandis (Oct 5, 2011)

xrunner said:


> No, not "nuff said" gentlemen.
> 
> 1st point - If your logic is right, then why paint anything having to do with safety and people - why paint aircraft, bridges, buildings, boats, busses, etc.. I mean, according to you all the cracks will be hidden!
> 
> ...


something tells me that wheel sets would be changed due to wear long before time (rust/corrosion) degraded the structural integrity. there cannot be enough rust on an axle or wheel to cause a problem before it gets changed for wear limits. a quick visual inspection for stress cracks would be hindered by paint.


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## xrunner (Jul 29, 2011)

gunrunnerjohn said:


> Yep, seriously. A number of aircraft are totally unpainted. I remember some rather ancient aluminum aircraft that were virgin aluminum and lasted very well. Here's even a cleaner specifically mentioning unpainted aluminum aircraft components: Cleaner for Aircraft Components, Cold Tank Type, Solvent-Base
> 
> American Airlines has a lot of unpainted planes, they polish the aluminum to keep it looking nice.


OK thanks.


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## norgale (Apr 4, 2011)

I think they don't paint the wheels to save money. Unpainted airplanes are lighter by many hundreds of pounds. More payload,saves money too. pete


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## gunrunnerjohn (Nov 10, 2010)

Yep, for a 747, it's about 800-900 pounds of "something" you can cram in instead of the paint.


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## xrunner (Jul 29, 2011)

gunrunnerjohn said:


> Yep, for a 747, it's about 800-900 pounds of "something" you can cram in instead of the paint.


Well I was going to drop the jets, but we're back at it again ...

If that's the case then why do they waste money painting _any_ airliners in this age of tight budgets? :dunno:


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## gunrunnerjohn (Nov 10, 2010)

That's actually pretty simple, marketing! The designs are to make each airline unique.


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## xrunner (Jul 29, 2011)

gunrunnerjohn said:


> That's actually pretty simple, marketing! The designs are to make each airline unique.


Isn't that what TV commercials are for? They require no paint ...


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## gunrunnerjohn (Nov 10, 2010)

Sure, and you show them a picture of your airplane, funny thing it looks just like any other plane. Remember, they're not like cars, there are only a handful of models that everyone flies! Almost every major airline has Boeing 737 planes, how do you make them unique? The logos and look are a major force in marketing, trademarks are everything.


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## New Berlin RR (Feb 11, 2012)

xrunner said:


> Well I was going to drop the jets, but we're back at it again ...
> 
> If that's the case then why do they waste money painting _any_ airliners in this age of tight budgets? :dunno:


because they want to make the planes look pretty...to attract the people to them....you know the whole bug and light senerio...


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