# Heavy wear operations



## gwscheil (Aug 6, 2008)

After 5+ years, the local club layout has logged over 6,000 hours on a dozen tracks. Wear is now very obvious. Metal wheel flanges are approaching razor edges in some cases. The last few plastic wheels were retired with deep grooves worn. Axle end bearings are showing pear shapes. Engines have needed extensive work - mostly USA trains diesels - motor bearings, plastic gears, are wearing out. Axle end bearings are a bear to redo but it appears that sintered bronze replacements can be installed, the spring wire power feeds appear to be standard 0.020" music wire. Every weekend the list gets longer. And black plastic dust is everywhere from wheels as well as truck pivots. Just replacing everything would be nice, but WAY beyond budget, so slowly we are finding inexpensive repair choices. Currently stuck on a simple solution for wheel/track wear. Anyone else have experience with high mileage operations?


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## Greg Elmassian (Jan 3, 2008)

You can turn the axle end bearings on the USAT 1/4 turn and get more life from them.

The gears will wear, but my first question is what is your maintenance/lubrication schedule and what is done?

Greg


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## gwscheil (Aug 6, 2008)

Ha Ha - very funny. Until I started coming last summer, there was almost no maintenance. If smoke was rising, someone who go investigate. Priority one is still to inspect everything and repair what is possible. Wear should drop as we limit the load - no more triple headers for hours on end. 15A power supplies are replaced with 3-5A so shorts do not vaporize wires, circuit traces etc. All smoke units are being disconnected. But then until last summer I was 95% live steam.


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## Greg Elmassian (Jan 3, 2008)

I don't think there is anything you can do to stop the flange wear, you probably have some tight curves... look for wear on the rail heads also.

Regular lubrication, and cleaning needs to happen, probably will double the life of the locos.

The spring wire pickups, are they burned looking at the ends, or just worn off? 

In usat, you need to make sure the sliders, axle pickups and the whiskers are ALL working, and that takes someone with an ohmmeter and some knowledge.

Don't just lube, make sure you don't have grit and dirt.

Add more locos to share the load, or run shorter trains... if you are triple heading, what is the train length, and max grade?

Greg


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## s-4 (Jan 2, 2008)

I worked at a museum that operated G scale trains daily on a timed push-button system. The owners swapped out the original brass rails at one point for stainless steel as an upgrade to reduce cleaning requirements. Unfortunately, this resulted in the same severe wheel wear as you describe. The solution was to use LGB ball bearing wheelsets in every car. The stainless steel wheels were able to rotate indepently of each other going around curves, thus reducing friction tremendously. Also since the axles no longer rotated, the truck bushings would no longer wear out either. Locomotive wheels, unfortunately, were still a maintainence issue, but were less intense due to the reduced train drag behind them. Regular lubrication practices usually allowed the mechanisms to live through several wheel-life spans.


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## gwscheil (Aug 6, 2008)

Answering various questions and comments:

The spring wires are frequently broken off - so new music wire is installed. Some sliders are fused in place, apparently from broken springs - McMaster-Carr sells replacement springs. Just a bear to remove the pieces and file away the debris and melted plastic. As we work our way through the locos, we flip them over in a foam U, apply power to each pick-up point in turn, note opens, etc. then pull covers and inspect gears, etc. lube as necessary, including USAT black conductive grease on the axle ends, inspect axle bearings for wear, replace, lube, and re-test as necessary. No good way found yet of doing a full inspection quickly - two of us take 1-4 hours per engine depending on condition. We really hate the 3-axle versions due to their habit of dis-engaging the coupling to the 3rd axle. Really wish USAT marked their wires better, very difficult to get the 4 wires back due to the very low resistance of the motors. And motors wired in reverse directions will blow PS mosfets in a second or less if you forget to check for direction of rotation before putting back on the track. 

We do have some tight curves, 8-10' diameter, but no grades. Many curves show heavy wear on the outer rail from wheel scuffing. All rail joints show erosion as that cute clickety-clack chips away at the ends. Anyone found a good way to do the equivalent of continuous welded rail?

Testing various cheap ways of reducing wheel friction and allowing independent wheel rotation - too early to report results there. 
I have had to be a little sneaky - by limiting the power units to 3A, each train is essentially limited to one powered engine, which means no 40-50 car trains and resulting wear on everything.
Passenger cars are in bad shape - back burner for now due to the complex wiring, etc.
It appears to be possible to reduce wheel wear on curves on rolling stock, but the engine wheels will wear because power must be transmitted to all wheels & miniature differentials are going to very tough to do. So the engine wheels are always going to do a crab walk around the curves. Increasing the tread taper might help in theory, but few wheels have enough metal to re-cut the treads.


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## Jim Agnew (Jan 2, 2008)

Putting a few drops of automatic transmission fluid on the rails on a monthly basis will go a long way in reducing rail and wheel wear.


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## Greg Elmassian (Jan 3, 2008)

The broken wires are probably because overcurrent heated the wire at point of contact, which also goes hand in hand with fused sliders...

Do you have derailments that last a while? 

Sounds like too much current being drawn, or some of the current paths fail and overload the others.

I'd make consists of locos, and wire between them to share the power pickup.

Also, REGULAR checking for cracked drive axles (the gear housing)...

Greg


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## gwscheil (Aug 6, 2008)

Derails usually last a while with no way to see all track from any two places, let alone a single watch station. Hence the shift to lower amperage power supplies from 15A monsters. Currently doing $25 eBay specials - laptop PS powering a 3A PWM DC motor control with reversing switch. One MOSFET failure so far due to operator error - engine with opposite turning wheels.


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## gwscheil (Aug 6, 2008)

Has anyone else tried to reduce wheel/track wear on curves by cutting the axles in the middle, then slipping a section of metal tubing over the cut ends? The tubing is cut to to length to prevent the wheels from falling between the rails, with nylon washer spacers as needed to reduce excess play. A quick test seems to reduce drawbar pull by 2-3 X on curves. The tubing will eventually wear through and the axle ends will still wear on the end bearings, but the crab walk should be gone.


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## Greg Elmassian (Jan 3, 2008)

George, one strong recommendation is to put "polyswitches" (which are often in Aristo locos) in to protect from a short, you need them basically on each independent pickup wire... It really sounds like these shorts and the resulting damage is a major factor.

I put them in every loco I service, and again, you are looking for shorts that can occur between the trucks when derailed, so you need basically one for every "pickup wire" that exists... in a typical USAT loco, this is 4 per truck, 8 per loco... you could also add one to each motor lead to protect from overcurrent, but I would NOT do this, because you can run into the situation where one motor is running the other off and the single truck will push the other one, tears up gears... you would be surprised at how often this happens and no one notices...

Greg


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## gwscheil (Aug 6, 2008)

Does anyone happen to have a source for just the plastic drive gears for USAT? We have a box full of wheel sets, but the gears died long ago. USAT wants to sell complete wheels/gear assemblies only. Twenty or thirty gears would be handy. Few have split shafts ( we can repair those) mostly worn toothless.


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## Greg Elmassian (Jan 3, 2008)

NWSL sells them, but not much cheaper than the wheelsets I believe.

If you have a box full of wheel sets, that means you guys are replacing them.

It is REALLY easy to assemble them wrong, and the loco will run, but will tear up the gears really quickly... Do you have just one person doing these repairs? No offense but do they really know the alignment of the bushings on the axles? Here's a really good test, just ask the guy who does the repairs if the bushings are aligned the same on the 2 axle trucks and the 3 axle trucks... if he does not know or says they are the same, there is a source of your problems...

Greg


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## gwscheil (Aug 6, 2008)

Yes, we know more than we want to know about assembling the creatures after stripping several all the way down for repairs - OK we haven't opened a motor can yet. But that is about all that was still intact. Very different gears in the 2 vs 3 axles, and a lot of parts that must mesh just so. I read all thru your site long ago. 

Remember I started looking into these repairs only recently - long after most of the wear occurred - maybe 6 running engines out of 20 at that point. Still inching our way thru the pile - all loops are active again, but only 3 or 4 engines are fully inspected and tested so far. Several more are running, but inspection usually shows repairs needed on the untested units. Where possible improving beyond manufacturer's specs. A slow process.


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## Greg Elmassian (Jan 3, 2008)

Thanks George, and no insult was intended, just wanted to be sure you "had it down".

So you are sort of a detective right now I guess.

The NWSL gears are supposed to be of a "tougher" plastic, but as I see you know, in the more complex gearboxes they are not the only gears at risk.

Greg


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## gwscheil (Aug 6, 2008)

Main lesson apparent after 6,000 hr operation - trains with plastic gears will not survive heavy loads. And electrics are not like live steamers - double heading is iffy, since most live steamers can be rolled by hand, so mismatched locos do not fight each other. So, any unit with more than one motor had better be very well matched or the stronger one will literally tear up the gears of the other. Oops, but then every curve you enter means that one motor block is now working harder. Nearly all engines I have seen have two separate blocks. If the motors were linked direct then they would share the load. Separate motors will fight each other - bye bye plastic gears. Or has someone found a way to get the friction low enough to free wheel an electric?


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## Totalwrecker (Feb 26, 2009)

Usually a worm gear stops the free wheeling. Unfortunately Spur gears aren't as reliable and are known to be noisy. Hence the worm.
John


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## Greg Elmassian (Jan 3, 2008)

George, have to disagree on your statement about "very well matched" on locos to run together.

Yes, I believed that too, buy just running 2 or more locos together and seeing the fighting.

But, under load, you will see the locos "share" the load to their individual abilities... so as long as they are reasonably close, this won't be a problem. I've proven this to myself over the years. If you think about it, it does make sense, since these locos will slow down under a load, therefore the loco going "faster" will take more of the load and will slow down to work with the other.

Most things are like I have said, not obvious, like one truck not running at all and it's gears being stripped. If you have burned up pickup wires and skates as you have stated, I'd bet this is a factor... not the only factor, but one to be reckoned with.

Regards, Greg


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