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Why the bare metal on wheels and couplers?

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Posted by wjstix on Tuesday, November 20, 2012 8:04 AM

Firelock76

I've been told in Germany the Deutsches Reichsbahn, later the Bundesbahn, painted the wheels of their steam locomotives red precisely because it was a lot easier to spot cracks.  Made sense to me.  I suppose the Russians and the Chinese did so for the same reason.

 
That's what I've heard also....
Stix
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Posted by 1019x on Monday, November 19, 2012 4:36 PM

Because paint can cover hairline cracks letting them grow and preventing early detection by car inspectors.

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Posted by Paul of Covington on Monday, November 19, 2012 11:44 AM

   Some years ago I remember reading that the reason for white-side-walls on many steam locomotive drivers was to show if the tire was working loose, which of course shouldn't be relevent on modern equipment.   To my eye, it made 'em look good, too.

_____________ 

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Posted by Anonymous on Sunday, November 18, 2012 10:53 PM

Here is an interesting thread with several different viewpoints on the subject:

http://www.trainorders.com/discussion/read.php?2,392186

On one hand, I can see the logic of prohibiting paint on couplers to prevent it from hiding cracks if the coupler is painted after a crack occurs.   Otherwise, it does not seem like paint would hide a crack. 

I heard that back in the days of cast iron wheels, trainmen might find a crack opened up and visible on a wheel that had been heated from braking.  However, once the wheels cooled, the crack would be invisible.  So they would stick some toothpicks into the crack.  That way, shop crews could find the crack and replace the wheelset. 

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Posted by Firelock76 on Sunday, November 18, 2012 4:48 PM

I've been told in Germany the Deutsches Reichsbahn, later the Bundesbahn, painted the wheels of their steam locomotives red precisely because it was a lot easier to spot cracks.  Made sense to me.  I suppose the Russians and the Chinese did so for the same reason.

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Posted by riogrande5761 on Sunday, November 18, 2012 3:01 PM

So I'm wondering if paint is withheld so as to not hide cracks, what about all the road grime that accumulates?  It doesn't take long for grime, grease, dirt etc. to obscure things like those important "cracks"  if the surfaces don't get naturally polished like coupler faces or wheel tread.  Either way, it seems to be an exercise in futility trying to keep the cracks visible if they were present.  While that sounds like a good idea, in real life, paint or dirt, still hides.  Paint would get worn off of some surfaces and dirt/grime while had those surfaces which don't get polished by wear.

Southwest Chief
Santa Fe used to paint the trucks and couplers on their passenger locos and cars silver.  Maybe even the wheels too, not 100% sure on that.  Of course they have long been out of the passenger business and not even Santa Fe anymore...BNSF.  I'd guess the no painting safety regulations likely came after the forming of Amtrak.

I read that Rio Grande used to paint their passenger diesel side frames for a short while, a very few years, in the 50's or early 60's, memory fails me on the details.  I do recall it was said the passenger engine side frames had to be painted about once every trip or every trip out and back to maintain appearance.  Obviously something so maintenence intensive and is costly and couldn't be justified for long.  As was the course of things, that practice was discontinued in favor of black trucks which didn't get repainted often.

Rio Grande.  The Action Road  - Focus 1977-1983

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Posted by episette on Sunday, November 18, 2012 2:18 AM

Paint them both semi-gloss black.

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Posted by Thomas 9011 on Saturday, November 17, 2012 9:22 PM

One of my jobs as a locomotive machinist and welder was magna fluxing parts and pieces of locomotives and cars looking for cracks. The wheels and the couplers were never checked. Having a crack in a wheel is so rare it is almost unheard of. I used to magna flux the frames of old Amtrak cars and there was so many cracks in the frame, that by the time I gouged out the cracks with a carbon arc it looked like a piece of swiss cheese. Most of these cracks are 1/4" or less and start and stop in the middle of the steel which is not a big deal. The wheels on a steam locomotive would be checked during a major overhaul.

They don't paint wheels for several reasons. One is that grease and oil will eventually leak out of the bearings and stand out even more if it was painted especially if it was white. Wheels get flat spots all the time and are frequently replaced. If they were painted someone would have to paint the new wheels to match the other 3 sets. Wheels take a beating. Even if you did paint them it wouldn't be long before there was chip marks all over them that would need to be repainted.

Not painting something to expose cracks is just a fairy tale. If someone is not painting something because they think it is going to crack soon then it shouldn't be on the road. Tank cars carrying deadly gas are painted. Locomotive frames are painted. Nuclear reactors are painted. It's actually easier to ID a crack if it is painted since a crack will usually chip the paint and rust making it stick out like sore thumb. Wheels and axles are checked for cracks (usually by X ray) at the factory. If there is no problems from the factory it is very unlikely it will fail later in life.

I guess you could paint couplers but they look just fine the way they are. Many steam locomotives do have the front and rear couplers painted black. I know some excursion trains do paint their wheels white or green. As said earlier Santa fe frequently painted their wheels silver.

 

 

 

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Posted by efftenxrfe on Saturday, November 17, 2012 7:03 PM

Driving wheels were vastly over-built, but not so their tires.  And locomotive inspectors, machinists, with their trusted relationship between their ears and hammer attended engines at terminals.

In the early 60's Santa Fe "refreshed" the truck frame silver at Richmond and the overspray on the wheels was marvelousely missed as examplesof abstract expressionist "art"

Doing the walkaround of the 10-hundred (S-6) I was given for a lead job at the Homestead end of West Oak yard I saw a fissure in the R4 wheel. after moving the eng  to allow goats in the spur to go to work and putting it back in the clear, the fissure grew to a quarter inch crack about 6 inches into the wheel. Shoulda' cut out the brake cylinders on that truck, right?

Which raises the safety question about the build-up of oil and dirt on wheels with leaking journal bearing seals, doesn't it?

    

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Posted by Rikers Yard on Saturday, November 17, 2012 6:10 PM

I take it that steam locos are exempt from this rule, never saw one with unpainted wheels, just askin'.

                                                                             Tim

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Posted by Southwest Chief on Saturday, November 17, 2012 6:08 PM

Santa Fe used to paint the trucks and couplers on their passenger locos and cars silver.  Maybe even the wheels too, not 100% sure on that.  Of course they have long been out of the passenger business and not even Santa Fe anymore...BNSF.  I'd guess the no painting safety regulations likely came after the forming of Amtrak.

Matt from Anaheim, CA and Bayfield, CO
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Posted by Anonymous on Saturday, November 17, 2012 9:18 AM

Doug,

That is exactly the explanation that I have heard.  Paint is specifically withheld from couplers and wheels so as to not obscure cracks. 

Paint is not withheld due to the futility of trying to get paint to hold up on these items, or to save money. 

If it were not for the safety issue, they would just spray paint the wheels and couplers as a matter of course.  Caterpillar paints the track plates and chains on their dozers despite the fact that the paint will wear off. 

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Posted by challenger3980 on Saturday, November 17, 2012 1:34 AM

My understanding is that, it is prohibited to paint Couplers (and possibly wheels as well?) because the paint could hide cracks that would otherwise be visible, preventing the defects from being detected before a complete failure of the component, which could lead to a derailment, or other damages, injuries or death. It is for safety reasons that those parts are not painted.

Doug

May your flanges always stay BETWEEN the rails

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Posted by Anonymous on Saturday, November 17, 2012 12:59 AM

Is this a serious question?

Any paint would wear off faster than you could put it on. There is no need to protect those parts from rusting, so why add to the bill by painting them?

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Why the bare metal on wheels and couplers?
Posted by gap920 on Saturday, November 17, 2012 12:49 AM

Why are couplers and wheels left un painted?  Does paint deteriorate due to heat?  Is it just the way we do it?

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