Author Topic: Excessive axle wear  (Read 1212 times)

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alhoop

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Excessive axle wear
« on: December 31, 2012, 09:29:03 AM »
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Several years ago there was a post on the A board about adding weight to
a N-Scale locomotive to increase tractive effort. I said be careful - that too
much weight might cause excessive axle/'bearing' wear.
Boy did I ever hear it - from a degreed engineer( never could find out where
his degree was from) and from a now current author for one of the N-Scale magazines.
While reading a list of publications from John Allen, I found my reference.
A reader asked in the 'Clinic' -Model Railroader magazine Jan 1955 -
"I have run one of my locos so much that the axle slots in the die-cast
main frame are worn out and the drivers wobble. What can I do about this?"

MR answer was to obtain a new mainframe - if available- or to install new
brass bearings after boring out the main frame.

So I got a life as recommended in the post and now post this for some peoples
edification.

Al

mmagliaro

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Re: Excessive axle wear
« Reply #1 on: January 01, 2013, 07:16:31 PM »
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At the risk of turning this into another ugly argument session (and yes, I do remember the old thread on this from the Atlas forum), I don't think the situation between a 1955 model and today is applicable.
Almost everything now either runs in bronze bearings, or in frame slots where the slots are made of very hard slippery Delrin.  In fact, as I think about it, except for my vintage Rivarossi steam and my Kato/Con-Cor S-2, I don't think I have anything where the axles ride directly in metal frame slots that could wear.  Heck, even the ancient Trix K4 has
the axles running in brass bearing sleeves. 

The Rivarossi frame slots can wear, so I have been told (although I've never had one do that to me).  But that's
an exception.

 I come down on the side of seeing any appreciable
axle or bearing wear as pretty hard to believe, even if you add more weight.


DKS

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Re: Excessive axle wear
« Reply #2 on: January 01, 2013, 07:27:55 PM »
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At the risk of turning this into another ugly argument session (and yes, I do remember the old thread on this from the Atlas forum), I don't think the situation between a 1955 model and today is applicable.
Almost everything now either runs in bronze bearings, or in frame slots where the slots are made of very hard slippery Delrin.  In fact, as I think about it, except for my vintage Rivarossi steam and my Kato/Con-Cor S-2, I don't think I have anything where the axles ride directly in metal frame slots that could wear.  Heck, even the ancient Trix K4 has
the axles running in brass bearing sleeves. 

The Rivarossi frame slots can wear, so I have been told (although I've never had one do that to me).  But that's
an exception.

 I come down on the side of seeing any appreciable
axle or bearing wear as pretty hard to believe, even if you add more weight.

I must agree. For as long as I've been in the hobby, I have yet to see any appreciable wear in an N scale locomotive. And some locos I've seen have run so long that the brushes have worn slots right through the commutators. I have seen siderods give out on a brass model that had only one driven axle, but this is a very rare exception.

The differences between the cited article and current reality are stark: back in the 50s, HO locomotives usually had steel axles turning in pot metal bearing slots, and given the greater mass possible in an HO locomotive with crude bearings, significant wear is believable (although it would more than likely be the bearings suffering, as opposed to the axles). But for N scale, you're talking about a fraction of the possible mass, with tiny axle surfaces turning in bronze or Delrin. IMO, this is an apples-and-oranges situation. I do not believe N scalers have anything to worry about with respect to axle wear.
« Last Edit: January 01, 2013, 07:30:49 PM by David K. Smith »
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PAL_Houston

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Re: Excessive axle wear
« Reply #3 on: January 01, 2013, 08:13:18 PM »
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I must agree. For as long as I've been in the hobby, I have yet to see any appreciable wear in an N scale locomotive. And some locos I've seen have run so long that the brushes have worn slots right through the commutators. I have seen siderods give out on a brass model that had only one driven axle, but this is a very rare exception.

The differences between the cited article and current reality are stark: back in the 50s, HO locomotives usually had steel axles turning in pot metal bearing slots, and given the greater mass possible in an HO locomotive with crude bearings, significant wear is believable (although it would more than likely be the bearings suffering, as opposed to the axles). But for N scale, you're talking about a fraction of the possible mass, with tiny axle surfaces turning in bronze or Delrin. IMO, this is an apples-and-oranges situation. I do not believe N scalers have anything to worry about with respect to axle wear.

...and for those running diesel locomotive models with trucks, the metal wheel/axle assemblies actually set into brass pickup/bearings, giving metal to metal support and electrical contact with very little friction and very slow wear rates.
Regards,
Paul

kalbert

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Re: Excessive axle wear
« Reply #4 on: January 01, 2013, 10:08:14 PM »
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"Texas has changed a lot since the 1850's Mr. Halloway" - Hank Hill

Most n scale locos have so much weight in them there's barely any room for a decoder let alone enough additional weight to make any significant increase in wear. Maybe if you stacked a bunch of weight on top. Maybe.

If my engines wear out I'll fix them or toss them but I'm not going to fret about it while I run them.

nkalanaga

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Re: Excessive axle wear
« Reply #5 on: January 02, 2013, 12:23:18 AM »
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Back in the 60s many MiniTrix locomotives actually had bearings.  The axles turned in brass tubing, which in turn fit the axle slots.  They were designed to be REPAIRED, not simply thrown away!

On the other hand, even then, they were among the most expensive ready-to-run locomotives made, so one really did get what one paid for.
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peteski

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Re: Excessive axle wear
« Reply #6 on: January 02, 2013, 01:07:58 AM »
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Back in the 60s many MiniTrix locomotives actually had bearings.  The axles turned in brass tubing, which in turn fit the axle slots.  They were designed to be REPAIRED, not simply thrown away!

On the other hand, even then, they were among the most expensive ready-to-run locomotives made, so one really did get what one paid for.

Weren't Arnold Rapido locos also equipped with brass sleeve bearings?  Nowadays most N scale steam locos have similar bearing arrangement.  Diesels don't need those bearings anymore because they use the needle-point axle-end bearings.
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nkalanaga

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Re: Excessive axle wear
« Reply #7 on: January 02, 2013, 01:30:47 AM »
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Peteski:  The only Arnold-Rapido loco I ever owned was the FA-whatever, and as far as I know, it didn't have bearings.  At least some of the MiniTrix diesels did, but again, I only owned one of the steamers, the 0-6-0, and it wasn't one of the earliest versions.

I've always modeled the late 60s or early 70s, and until the late 70s, had to watch the budget, so steam was neither needed or affordable.  The few I did have, mainly the MiniTrix PRR 0-6-0 and the MRC 2-8-8-2, were mostly because my father liked steam. 

I wish someone would make that MRC model again.  It runs at least as well as any steamer today, but mine needs a new eccentric crank on the front engine.  It still runs fine, but looks a little odd.  It also doesn't fit the BN in 1974, but maybe it belongs to a museum group somewhere.
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DKS

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Re: Excessive axle wear
« Reply #8 on: January 02, 2013, 06:03:51 AM »
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Back in the 60s many MiniTrix locomotives actually had bearings.  The axles turned in brass tubing, which in turn fit the axle slots.  They were designed to be REPAIRED, not simply thrown away!

Yes, these were very well designed models--I have several dozen at least. But even the oldest and most-used of them show no signs of axle wear, even after decades of use, and they have about the most mass one can cram into a cab shell.

IIRC, it was a Märklin Z Scale diesel that currently holds the world record for endurance, and I believe it failed owing to the motor commutator wearing out.
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pnolan48

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Re: Excessive axle wear
« Reply #9 on: January 04, 2013, 12:51:23 PM »
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What is that record?

I had long running loops (6 miles and 30 miles) on my layouts, and ran diesels pretty much non-stop while I was working on details. Some of the engines must have thousands of hours on them. The Bachmanns failed when the axle gears cracked, but this might have been a matter of time rather than distance, as they also cracked sitting in a box. The Katos failed when I let the engine shaft bearings get too dry. I've never seen a hint of axle wear, although I have seen extensive wear in the bearing cups. I'm not a maintenance freak and lubed engines only after I had cleaned them, which was infrequently.

randgust

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Re: Excessive axle wear
« Reply #10 on: January 04, 2013, 01:56:27 PM »
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We have an HO display layout in our front window.   It used to run constantly, we upgraded it to a 3-minute timer on a demand pushbutton.  It's basically two loops on a 5x9 with sharp curves and grades.

I evolved into two locomotive types to keep it going; for steam, an IHC Consolidation, and for diesels, Mantua GP20's.

If you've never seen model equipment run 24/7 until it completely drops, it is remarkable.   Here's a few things I observed that may be transferrable to N:

1)  Steel axles can, and will, wear right through delrin truck bearings, if there is the slightest irregularity in them.  I've also seen them wear right through end axle pickups (brass)
2)  The first thing to go on steam locomotives is usually the rods/crankpins.   So lubricate them.  I use neolube.
3)  I've never, ever, ever had nylon/delrin gears wear out that were properly lubricated with synthetic lubricant.
4)  I have had delrin axles on delrin bearings wear right through and snap off on locomotives, again, missing lubricant.
4)  First thing to go on diesels is the plating on the wheels, not always a bad thing, either.
5)  It is possible to wear the flanges right off of brass wheels.  I've done it.

Other than regular wheel cleaning and lubrication, I tend to just put them back on the track, and as long as they run I don't mess with them.  The most spectacular accidents I've had is a Consol pole-vaulting itself off of the layout to the floor when the crankpin wore through on the main rod, and the second spectacular one was a GP20 driving right off the layout with an entire train behind it when the flanges wore out and folded over.

Oh, and I weight my N stuff up to maximum, until motors start to run warm.  But I do neolube the rods and lubricate a little heavier than most I think.
« Last Edit: January 04, 2013, 02:02:21 PM by randgust »

DKS

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Re: Excessive axle wear
« Reply #11 on: January 04, 2013, 02:09:53 PM »
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What is that record?

I am trying to find out. I believe it might be in Guinness.

We have an HO display layout in our front window.   It used to run constantly, we upgraded it to a 3-minute timer on a demand pushbutton.  It's basically two loops on a 5x9 with sharp curves and grades.

I evolved into two locomotive types to keep it going; for steam, an IHC Consolidation, and for diesels, Mantua GP20's.

If you've never seen model equipment run 24/7 until it completely drops, it is remarkable.   Here's a few things I observed that may be transferrable to N:

1)  Steel axles can, and will, wear right through delrin truck bearings, if there is the slightest irregularity in them.  I've also seen them wear right through end axle pickups (brass)
2)  The first thing to go on steam locomotives is usually the rods/crankpins.   So lubricate them.  I use neolube.
3)  I've never, ever, ever had nylon/delrin gears wear out that were properly lubricated with synthetic lubricant.
4)  I have had delrin axles on delrin bearings wear right through and snap off on locomotives, again, missing lubricant.
4)  First thing to go on diesels is the plating on the wheels, not always a bad thing, either.
5)  It is possible to wear the flanges right off of brass wheels.  I've done it.

Other than regular wheel cleaning and lubrication, I tend to just put them back on the track, and as long as they run I don't mess with them.  The most spectacular accidents I've had is a Consol pole-vaulting itself off of the layout to the floor when the crankpin wore through on the main rod, and the second spectacular one was a GP20 driving right off the layout with an entire train behind it when the flanges wore out and folded over.

Oh, and I weight my N stuff up to maximum, until motors start to run warm.  But I do neolube the rods and lubricate a little heavier than most I think.

I can completely believe all of this; I've witnessed it myself, having worked in a hobby shop in my college days and having built window displays for them. Once again, though, you're talking about HO, where the physics involved are quite different from those in N. Much more mass. Larger bearings. Greater friction. It all adds up. Now, I won't go out on a limb and say that such wear is impossible in N scale across the board, but I would bet a handsome sum that a modeler--even one who runs his/her trains much, much more than normal--will not experience this, except possibly through neglect. To date, I've not seen any myself.
« Last Edit: January 04, 2013, 02:12:58 PM by David K. Smith »
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Freight Train

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Re: Excessive axle wear
« Reply #12 on: January 04, 2013, 07:55:17 PM »
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The only thing that I ever saw of excessive wear was when I purchased a SW 1500 switcher from an individual online. If was sold as used and what I do with all used locos is to tear them down clean and re-lube them. So while taken this switcher apart I notice a wear hole in the frame were the truck makes electrical contact with the frame. I don't recall off hand if it was a Arnold or Concor (Kato) frame but it made me wonder what that poor little switcher went through before I got it. It ran perfectly fine with the hole in it. Always wondered if it ran on a mountain type layout were the percent grade was higher than normal?? Never seen anything like that before or after. And none of my equipment ever shown signs of wear anything close to that.
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