Model Railroading > Interesting wheel problems

I have a 10 by 20 HO train display which I have posted photos here on TO.  It is DC.

I began having problems about 5 years ago with the trains.  They run during bank lobby hours.  Up to 8 hours a day.  Locos would slow and eventually stop.  At first I thought it was the power packs because they were very warm.  I replaced them and the problem continued.

Last year I posted the problem here on TO.  The culprit seems to be the plating wearing off on the newer locos: Atlas, Proto, Walthers, and Athaern, all developing the same problem.

Photo 1 shows where the plating is worn away.  It turns out that it is mainly on the + rail.  Photo 2 shows it more clearly.  A,B and D show the + side of the wheel.  C and E, E more clearly, show the - side  wheel.  

So, the plating wears off then the exposed wheel then micro sputters and builds up resistance to the point the motor over heats.  The rail on the + side gets pretty dirty.

This year an electrician mentioned that perhaps it is reverse plating.  Is this possible?

I am replacing the wheels with older wheel sets (mostly Athaern ) and the problem is not evident yet.  Some of the replacement wheels now have over 80 hours on them.  I would guess that the problem develops after the third year of running with the plated wheels.  I have about 25 locos to rotate through during the 30 day run.  Any given loco probably runs up to 16 hours a week.



 

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Dan;  

   I presume you're using nickel silver rail.  There was a time when brass, and even steel, was used.  Oxidation was a real problem in those days.  Can't recall wheels having a problem like this before.  It will be interesting to see how other T.O. members respond.

NWSL makes solid nickel wheels.  Page eight has some interesting information.  http://www.nwsl.com/uploads/chap3_web_09-01.pdf

Larry

There's no reason for electrical resistance at the wheels to make the motor overheat. If you're using DC the voltage at the motor would simply become less.

Are you using DC or DCC or anything other than plain old DC?

Is the track in a simple loop? What is the minimum radius? Wondering if there are left turns and right turns or just 4 turns in the same direction. It would be interesting to know the rail composition, Nickel Silver I would think, and if all the tracks are the same manufacturer. Are the power feeds soldered or mechanical, screws or crimps, or whatever. Do the wires show any change in flexibility, or discoloring?

+Agree the plating has simply worn off. The motors overheating could be the friction bearing at the motor frame. Recently experienced high current, odd noises and then a complete freeze up and blew a power pack circuit breaker. Simply added a drop of heavy lubricating oil, not grease, the motor did not exhibit problems after that, but I'm still testing.



Edited 1 time(s). Last edit at 12/10/15 14:48 by TCnR.

Had a yellow box Atlas S-4 that had the same problem after about 15 years of use.
I talked to Atlas and they told me plating is probably gone from use.
I called NWSL (very helpful) and replaced the wheels with NWSL 88 tread solid nickel silver wheels.
Excellent results and I'll never wear those solid wheels out in my lifetime!

Regards,  Jack

The layout is an oval 1 scale mile long.  Plain old DC.  I said I touhght the locos were over heating because the power packs (MRC) were quite warm.  All NS track and the track is clean.

TCnR Wrote:
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> There's no reason for electrical resistance at the
> wheels to make the motor overheat. If you're using
> DC the voltage at the motor would simply become
> less.
>
> Are you using DC or DCC or anything other than
> plain old DC?
>
> Is the track in a simple loop? What is the minimum
> radius? Wondering if there are left turns and
> right turns or just 4 turns in the same direction.
> It would be interesting to know the rail
> composition, Nickel Silver I would think, and if
> all the tracks are the same manufacturer. Are the
> power feeds soldered or mechanical, screws or
> crimps, or whatever. Do the wires show any change
> in flexibility, or discoloring?
>
> +Agree the plating has simply worn off. The motors
> overheating could be the friction bearing at the
> motor frame. Recently experienced high current,
> odd noises and then a complete freeze up and blew
> a power pack circuit breaker. Simply added a drop
> of heavy lubricating oil, not grease, the motor
> did not exhibit problems after that, but I'm still
> testing.

That explains your wear pattern on one wheel and not the other, especially if it's a fairly tight radius. Everything you are seeing is very normal so far, just a lot of metal to metal wear. You'll probably notice the ends of the rail, at the rail joints, showing some sort of mechanical deformity. Either mushed down, or collecting gunk, etc. Perhaps the inside of the outer rail on curves will show deformity of some sort as well.

santafedan Wrote:
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> The layout is an oval 1 scale mile long. 

Your heating problem is possibly the motor condition as mentioned above, as the frame and motor shaft heat up they expand and the motor has to work harder to turn, the train and gearing resistance will be the same but the internal physical resistance of the motor will increase. The train will slow down, needs more throttle and so on.

The power pack is probably not built for such loads over that time frame. It needs a metal heat sink or a fan, but the internal solder joints and such will be stressed and possibly fail. It would be interesting to get a sponsorship from model locomotive and power pack manufacturers to get some stressed run time on their designs.
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