# Main reason for Mikado/Mallet drivers coming loose on axles



## Rayman4449 (Jan 2, 2008)

I finally got around to documenting and posting pictures as to what I was talking about in other threads about the inside of the driver being too narrow at the end.  (I know this is an old discussion, but what I found in my analysis is not something that was ever discussed here before.)


I'm not going to duplicate the write-up here, see the link below.  Again, this is only to assist with troubleshooting and not to start a discussion on QC.  The more we know about a problem, the more effective we will be at resolving it.


http://www.rayman4449.dynip.com/Aristocraft_Mallet_Modifications_page.htm


Raymond


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## Curmudgeon (Jan 11, 2008)

Unfortunately, there are more than one reason. 
The axle machined too far, or the wheel too deeply, allowing ANY axle to protrude, preventing washer and screw from tightening against the wheel proper............gauge too narrow (see above), causing outward pressure at turnouts to dislodge wheels from axle. 
As you found, improperly machined wheels. 
It isn't worth my time to fix them anymore. 
I had a NEW Pacific through here late last year, gauge so bad it was unusable. 
(G1MRA, old nmra, 1.575" back-to-back, + or - about .010". check gauge from wing rail of frog to guard rail, about 1.535", Pacific at least two drive axles UNDER 1.530")


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## Rayman4449 (Jan 2, 2008)

Hmmmm... Maybe reread my post.  It doesn't cover just one issue.
 
Makes me wonder how frequent an issue the under gauge problem is.  So far I've personally dealt with 8 of these blocks and none have had issues with gauge to the point where it has cause any issue at all.  But, if your engine hits a turnout with that type of gauge problem should become apparent real quick that you have a bigger problem... one that's beyond the scope of a teetering driver.

I guess it's good that this is an issue you don't have to worry about any longer.


Raymond


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## Curmudgeon (Jan 11, 2008)

First real issue was the SD-45. 
With measured gauge less (sometimes a LOT less) than turnout check gauge, and with the big weights the early ones had, we watched with utter fascination the reports of "broken axles". 
Wasn't. 
A 13-pound locomotive, running at Warp Factor Two, hitting a properly gauged turnout when the wheels were not, well, remember the bit about and object in motion tending to stay in motion in that direction? 
The locos did not go UP, the wheels went OUT, ripping the screws out of the worm gear. 
Takes about 2.5 hours per truck to re-shim. 

First thing you do is look at the axles, see if they protrude from the wheel flats, then check the gauge. 
If it's wrong on either account, and you don't feel like messing with it, let the manufacturer do it. 

Fixing a wobble due to a non-fully-machined wheel is fine, but what happens to the gauge when done? 
What was your back-to-back?


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## Rayman4449 (Jan 2, 2008)

Holy crap, I hadn't heard about the broken axles, but I'm a relative latecommer to the G scale scene. (2004)  I guess that's not surprising but I would imagine that would freak most people out.  /DesktopModules/NTForums/themes/mls/emoticons/shocked.gif   I think I would be horrified.  

I didn't measure the gauge as I wasn't worried about gauge changes because any change would be by a miniscule amount.  I'm not wearing down the whole taper  surface, just getting them to fully come in contact and they really didn't have far to go.  I've never had a derailment or any issues going through turnouts before or after my modification.  

Raymond


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## Curmudgeon (Jan 11, 2008)

Depends on the turnout. 
If it's a "sloppy" turnout, made to "no known standard", probably not an issue. 
However, if you are using a closer rail height, often that will equate to a more rigorous application of the turnout standards. 

Before you do anything (in any scale, basically), before you even put it on the track, check the wheel gauges. 

G1MRA and old nmra was/is 1.575" back-to-back, with about a + or _ .010". 
Check gauge on your turnouts, from the frog wingrail to the guard rail, is about 1.535". 
Miniscule is a loaded word. 
Let's say the check gauge of your turnouts is 1.535". 
Let's further surmise the back-to-back is WAY out, at 1.536". 
Let's just then guess that your "miniscule" amount is .002", which, truthfully, IS minscule. 
However, you just went from "barely passing" in clearance to "totally failing". 

What IS your wheel gauge? 
Why do you think I report all wheel gauges in the reviews? 

You REALLY need to know those numbers.


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## Rayman4449 (Jan 2, 2008)

I don't disagree that it's important.  And if I went from clearing the turnouts to not clearing the turnouts, I would have seen a problem, which I didn't.  At some point I may check them, but I've watch my engines go through my turnouts at very slow speeds many times.  If there was serious problem with them being undergauged, I'm pretty certain I would have noticed it.  If drivers were having to be corrected for position going through a turnout as would happen in this case, I would see it.  The next time I take them out I'll watch again.  

Thank you for pointing out the undergauge issue.

Raymond


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## markoles (Jan 2, 2008)

TOC,

I think I finally am starting to understand the reason for the back to back wheel standard.  Humor my ignorance.  

Your loco with wheels spaced at 1.530 is running down the track.  As it passes through a switch, the guard, with a fixed gauge at say 1.560, pushes the inside of the wheel OUT.  Since the wheels we are dealing with are mounted to axles and held in place by a screw and loctite, the moment caused by the flange being pushed by the guard causes a torque on the screw.  This must be what causes the scew to back out, allowing the wheel to work itself loose.  I have noticed that the plating on the inside of my RS-3 wheels looks like it has been rubbed off.  Maybe that's what was causing that.

Ray - I think that the weight of the locos is more than what the interference (potential) force can produce to push the locomotive up.  Maybe take a look at your guards and see if they are showing signs of wear.  I am using Aristo Wide Radius switches, and haven't noticed many problems with my Mikado.  The lead drive axle on was loose last summer and a repair and reapplication of loctite has has held so far.   Thanks for taking time to document a better fix.

Mark


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## Rayman4449 (Jan 2, 2008)

Thanks Mark,

Oh boy, in your case that sounds like the gauging could be a problem.  I don't envy you getting that fixed!  /DesktopModules/NTForums/themes/mls/emoticons/crazy.gif  I'd be interested to hear what you find out.  I'd also be interested to hear how many engines you have, what type (steam or diesel) and how many (if any others) are displaying this problem.   

At the end of this year I was outside grinding down my railguard ends (so they didn't rip my track cleaner pads off) and didn't see any sort of wear at all on them.  I may just be lucky, but I have 7 Articulated steam, 6 single steam and 7 Dash-9s and I haven't had any issues.  I've also had my engines on their backs periodically for maintence and I've not see any sort of impact scratches or wear on them on the inside of the drivers.  I'll just thank my lucky stars.    

If the taper surfaces are properly mated together, the forces the driver sees from normal running or any other impact should be absorbed by the adhesion of the taper surfaces (transmitted direct from the driver to the axle) and not the screw.  If they loose their adhesion, then I would imagine the screw will start could see an increase in the force it sees.

I also think that if an engine has too narrow a gauge problem and it goes through a turn out, you should see (on the steamers) the driver axle pairs that have the problem make a side to side directional correction the second they make impact so they can attempt to go through.  I've never seen that on any of my steamers and I have watched each and everyone of them go through my turnouts very slowly.  I will agree that the time to catch it is before the engine hits the track for the first time and not when it's actually happening.  

On the 'rub ring' problem...  Before I ran my Mallets for the first time, I had them all on their sides checking each motor block and drive train for smoothness and checking for out of quarter issues and binding.  It was in this inital testing that I found the ones that were loose.  At first I found one that was really loose and then started to test each one by trying to turn them by hand.  That's when I found a large number weren't secured well to the axle.  

Raymond


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## aceinspp (Jan 2, 2008)

The thing about guard rail is that they are made to do exactley what the word means guard.  Its purpose is to make sure the wheel flange does not hit the frog point.  Many of the AC turnout are so far out on guard check and guard face that the wheels strike the frog point.   If the guard rail is doing its job it should show some wear.  Also problems on early productions of SD45 motor blocks had in correct back to back gage.  Later RJD


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## Guest (Jan 21, 2008)

7 Dash -9's, oh crap i need to get going your catching up   HE HE HE  just kidding but with all this talk of how crappy these steam loco's are i think the 2 that i have will be the last, i will stick with usa a least they run right, out of the box and as for the dash's i think i'l have reavaluate them as well. the macks finally showed up today at the dealer, they assured me they were on the way, ray  look at that i made a ryme [ on the way Ray]   i crack myself up... and i'm sure theres others that would like to crack me up too!!!/DesktopModules/NTForums/themes/mls/emoticons/hehe.gif
Nick


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## Rayman4449 (Jan 2, 2008)

LOL  No worry, you are firmly in the lead and I probably won't overtake you for the title for most diesel toys.  LOL  /DesktopModules/NTForums/themes/mls/emoticons/laugh.gif 

I certainly understand it if you decided on doing that, but I would feel bad if that is how everyone was taking my posts.  The unfortunate reality is Largescale has QC issues and just about everyone has them.  USA T steam is top notch, there is no doubt.  Heck even my USA T Big Boy had problems!  I've reported on the MTH steamers in the past, lots of detail stuff and I'm only just now getting around to the Aristo items.  It's a decision everyone has to make, but with selections being so limited if we skip on a model, there isn't much else to replace it with.  I'm trying to help us and the mfg by reporting this stuff back so maybe they can address them at the factory and to make the do-it-yourselfers more effective at resolving their issues.  But for those who don't have the desire to tear into their engines, I certainly understand if it creates hesitation.  The only consolation I can provide is the mfgs I've dealt with have all made issues that I've presented to them right.  Aristocraft, MTH and USA Trains all have stood behind their products I've purchased.  Aristocraft is particularly great because they make themselves so available to questions and assisting their customers.  I mean when I can send an email to the president (Lewis) on a Friday afternoon and he replies the next morning on a Saturday, I mean you just can't complain about that.  I'm very thankful for the help I've received.  Now while an engine may be down for a bit, it does ultimately get corrected.  I think the biggest issues seem to be with the steamer because of their complexity the resulting greater cost of production and need to hold down costs.  Seeing a mfg get stuck with tons of engines they can't sell cause folks are afraid to buy them is something I don't want to see.  We all loose if that happens.  /DesktopModules/NTForums/themes/mls/emoticons/sad.gif

Raymond


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## Greg Elmassian (Jan 3, 2008)

I certainly am not here to knock any products. The USAT products can be gauged to meet current standards with a press. The Aristo products need shims or grinding to meet gauge. The design of the modular power unit is interesting, but it needs to be taken out of the loco and taken apart to add shims to regauge the wheels. There is someone who sells the shims, but adding $25 - $50 per loco and all the labor to boot starts to wear on you. Virtually all my diesels are USAT. I have all the more modern steam Aristo makes, but I will be working them all over. It makes buying an $800 loco make more sense (Accucraft AML line). 

Ever since I started paying attention to back to back gauge on rolling stock, and guardrail flangeway widths on my switches, I went from 6 car trains to 40 car trains with extreme reliability. I'm sold on good trackwork and following back to back spacing on wheelsets. 

Regards, Greg


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## Stan Cedarleaf (Jan 2, 2008)

Raymond, the Mallet sure is nice with the new paint.  I like that look a great deal.  Just something special about it.  Great article.  Thanks


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## Rayman4449 (Jan 2, 2008)

Thanks Stan.  I agree, the painted drivers really set the engine off.  They really are a great looking and impressive model.  

Raymond


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## Grant Kerr (Jan 2, 2008)

Ray 
I believe that this may just explain to you what TOC is trying to discribe. A picture is always worth 1000 words. 

mywebpage.netscape.com/soundgk/page17.html


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## Rayman4449 (Jan 2, 2008)

Hey Grant,

Thanks for the link.  Couldn't get it to work at home but did at the office.  That's pretty bad.  I did understand what TOC was describing.  As I tried to explain, I have not seen that problem on any of my engines and that it's not related to the loose drivers on my Mallets.  I acknowledged that I agree it would be a serious problem.  Not sure what else I can say.


Raymond


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## Dougald (Jan 2, 2008)

Raymond 

I think the point was simply that you really should check the gauge. Most folks who have never seen this problem use Aristo or LGB track. Those of us using third party switches (I use Llagas Creek) do see the problem fairly often. 

Regards ... Doug


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## markoles (Jan 2, 2008)

Ray,

I don't think your post about how you repaired a problem will lead to a downturn in sales for these aristo steam engines.  Frankly, I think that the pacific and mikado should have be re released with more detailed shells and of a standard USRA design, but that's horse has been so thoroughly beaten, we won't go there again.  I use the Aristo switches, and haven't had a problem (and the de-plating on the inside of the RS-3 wheels might be due to something other than hitting guard rails).   My wheel loosening situation is totally self inflicted.  I removed the wheels for painting.  To this day, I keep an eye on the Fireman's #1 driver.  Another thing that I think could be improved is the grade of the hardware aristo uses.  Every single Aristo engine I have taken apart and put back together has at least one stripped screw. Cheap hardware. 

You touched on an idea that I think has also been discussed, that of QC for steam engines.  We are on the brink of the 2nd steam engine release from Aristo with their new Prime Mover drive train.  I think your post here and on Aristo is timed very well and points to a specific manufacturing item which, if addressed at the factory, stands to improve the forthcoming product substancially.  Aristo is not the only ones with steam engine issues.  
I can think of instances for every single manufacturer, but like Ray says, all manufactures stand by their products and make them right, to varying degrees. 

How many Aristo Live steam Mikados had wheels come loose on the axles?  Is that a totally different assembly? And those wheels come painted. Why aren't the electric engines' wheels painted, too?

Mark


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## Rayman4449 (Jan 2, 2008)

Posted By Dougald on 01/22/2008 9:02 AM
Raymond 

I think the point was simply that you really should check the gauge. Most folks who have never seen this problem use Aristo or LGB track. Those of us using third party switches (I use Llagas Creek) do see the problem fairly often. 

Regards ... Doug

I hope everyone got the point, I certainly did.  What you just mentioned on the third party switches I think adds some clarity on why this seems to be a serious issue for some but not others.  The track pictured in Grant's link didn't appear to be a USA or Aristo.  

My point is that for the issue of loose Mikado/Mallet drivers, we really should check the outside taper of driver as a key underlying cause.  As I said before, the fact my drivers were loose had nothing to do with the gauge, as they were loose before the engines ever hit the track and this was the reason.  That was why I started this thread, to report what I found...  an issue I've not heard mentioned before.  
  

Raymond


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## Curmudgeon (Jan 11, 2008)

To give you an idea, old LGB 1600 turnouts measure 1.500" check, frog wing rail to guard rail, OR LESS. 
This is .035" narrower than "standard". 
It also causes properly gauged locos (like the new K) to pick the point of the frog. 
You need to have gauge on wheels right, and gauge on turnouts right.


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## Rayman4449 (Jan 2, 2008)

Hey Mark,

I would hope that overall posts like this wouldn't.  (I agree with you on the Pacific and Mikado by the way)  

I found that too that once you remove a driver it was hard to re-secure it.  What I partially concluded was that because the driver tapers weren't really mated, the gear box grease was getting on the taper and making the problem worse.  And also, I had to clean the surfaces with alcohol to get the grease off.

Very good point on the timing of the Aristo Northern release.  If they can solve the driver coming loose problem, there really isn't anything else of major consequence that (that I have personally experienced) that would give headaches.   Redoing the drivers and axles was time consuming.  

I hadn't heard about any issues with the live steam but would imagine that it's a different setup as the electric drives the drivers from power from the gear boxes as opposed to the outside cylinders and connecting rods.  (I assume this is how it works on the aristo)

It probably won't be long too (maybe 6 months) that MTH will release their triplex.  I'm interested to see what if any issue we encouter with it.  With the past history on the Big Boy I already know a number of things I will be looking at and for right off the bat.

Raymond


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## H-man (Jan 4, 2008)

Gentlemen, I have 5 SD45 and am only able to run 2 as the wheel gauge is too narrow. Run fine through the LGB switches but derail on the Micro Engineering number 6s. Just haven't taken the time to repair so they sit on the shelf. Also have problem with the USA sliders picking points on switches and tearing them out of the power trucks by the roots. This makes a huge mess of a 50 car train. So some of them sit as well. 

Love this hobby, Really makes one think from time to time. 

Howard


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## Rayman4449 (Jan 2, 2008)

This is even more evidence this is an issue that seems to be mainly with non-Aristo and USA Trains switches, etc.

Raymond


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## Greg Elmassian (Jan 3, 2008)

It would be nice if people would post the back to back they have measured on their locos. Only TOC has posted it. I'll check mine this weekend and see. 

(I've been afraid to because then all the work I will HAVE to do will bug the heck out of me!). 

But, I have my Northern, made from 2 Pacifics, apart, so it's a perfect time to see what I can do about gauge. 

Also, if you "fix" your Aristo switches for proper guardrail geometry, then, while properly gauged wheels will run much more reliably through them, the possibility of tearing the axles out of the gear in the locos becomes even more likely. 

Argh, you just can't win! 

Regards, Greg


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## Dan Moore (Jan 3, 2008)

And  everyone is bustin on Bachmann Quality !!!


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## Greg Elmassian (Jan 3, 2008)

Yeah, all we do is complain!

Actually this has been a problem for a while, but now people's locos are getting to the point that this stuff is happening. Nice to know it before it happens to you and you twist your rod gear into a tangled lump!

Regards, Greg


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