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Balancing Steamers to Maximize Driver Traction

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Balancing Steamers to Maximize Driver Traction
Posted by Attuvian on Thursday, September 13, 2018 5:52 PM

Late last night Dr. Wayne provided responses on the Electronics and DCC Forum in a string entitled "How to Repair the Wiring Harness on a Athearn Genesis 282 Light".  In his last response he included a link to a 2009 spread that he did on 2-8-2 mods on the Bluetrains forum.  As is all his stuff on behalf of the community, it is a masterful presentation, replete with photos and step-by-step instructions - including particulars on the casting of customized weights from scrap lead to maximize loco pulling power.  He spoke of the importance of the engine's weight being evenly distributed across the wheelbase of the drivers for best effect.

This piqued my interest immediately as I have two Genesis SP Mountains that likely will need the treatment once I generate enough courage to open them up.  But I am a bit unclear on two points: 1) I presume that the balancing should take into account the entire engine upon its reassembly, and 2) what method and devices (jigs, etc.) are used in the balancing process?

I fully expect Wayne to chime in here - in spite of all the other stuff that he has to do.  But I will also look forward to what other advice (and gizmos) come from the rest of you steamer mechs out there.  Photos will be icing on this cake.

With much appreciation, as always,

John

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Posted by 7j43k on Thursday, September 13, 2018 7:46 PM

Attuvian

1) I presume that the balancing should take into account the entire engine upon its reassembly...

I'm not sure I follow you.  If you're talking about the lead and trailing trucks, they're mostly decorative on a model.  The balance point should be the middle of the driver wheelbase.

 

2) what method and devices (jigs, etc.) are used in the balancing process?

 

 

Place the locomotive on a "plank" that is strong enough to support it.  Balance this assembly on a dowel or pencil.  The balance point should be as mentioned above.

 

 

Ed

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Posted by peahrens on Thursday, September 13, 2018 8:25 PM

I've never thought about it so will be interested in what can be offerred.

I'm recalling that friction force is proportional to the friction coefficient (wheel to rail) times the force (weight) applied.

https://en.wikipedia.org/wiki/Adhesion_railway

That being the case, if we had a 0-8-0 with center of gravity not over the midpoint of the 4 axles, let's say towards the last axle, the forward axles would lose tractive effort and the rear axles would increase their effort and it would tend to come out near the same.  Two caveats come to mind.  If the drawbar to the tender started picking up some of the out of balance force, some of the loco weight would transfer to the tender for a net (tractive) loss.  If nearly all the weight were over the 4th axle, it would be ok (if that axle not on an especially slippery area)??  I may be missing something here.

This would be complicated by:

a) one axle having traction tires, perhaps, where the friction factor for that axle is higher, so the more weight force there, the better.  I'm assuming that the traction tire and bare wheels have equal radii and are touching simultaneously.

b) sprung drivers, but that might not matter much as long as none are bottomed out.  While the axles with least spring compression would get less weight (downforce) the other axles would make up for that (the weight sum being the same)??

c) leading and trailing trucks.  If the trucks had much stronger springs than needed to barely help them track adequately, they would be stealing weight (downforce) from the driven axles / wheels and reduce traction.

I'm thinking the keys are:

(a) the more weight, the more traction, and the center of gravity (if there are leading or trailing trucks) should simply be within the front and rear driven axles (more precise centering may not matter much), and

(b) excess weight that is sprung to the lead and/or trailing trucks is wasted weight = lost traction.

It's late, so I may have forgotten some physics or am overlooking practical basics that apply.  I'm guessing that only extreme out of balance / springing could be an issue of significance.  Just my hypothesis, may be way off!  Be kind with pointing out what I am missing.

 

Paul

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Posted by doctorwayne on Thursday, September 13, 2018 11:43 PM

John, the loco is fully assembled for the balance test, even though the lead and trailing trucks have little weight to contribute and are mostly supported on their own wheels.
As Ed mentions, you can create a balance with a piece of wood and some dowel - I made mine from a sheet of brass, with heavy brass wire soldered across its balance point. 
Even if the loco is picked up, with thumb and finger on the running boards in a light grip, and at the mid-point of the driver wheelbase, you can get a pretty-good sense of how well it is (or isn't) balanced.

Prior to doing the modifications outlined in that thread, I placed one of those locos and its tender on the layout, then draped a "saddle" of folded sheet lead over the boiler, and while restraining the tender with my hand, applied power.

The locomotive attempted to surge forward, then immediately slipped its drivers, a sure sign that the weight was not too much for the motor to handle.  As I recall, that "saddle" was well in excess of two pounds, and of more volume than could ever be fit into that locomotive.
If you have diesels and think that weight could help increase tractive effort, you can do a similar wheelslip test by coupling a car to the diesel, and holding it in place, as I did with the tender.  Most diesels I've owned seem to have been pretty well-balanced, but I did add weight to pretty-well all of them....my layout is mostly grades and curves, usually occurring in the same places.

The Athearn USRA locos (Mikados and Pacifics) both came with springs on the trailing truck, and I think that its main purpose was an attempt to shift some of the imbalanced weight forward. 
If you complete the outlined modifications, the spring should be removed - the truck tracks well without it, and leaving the spring in place will create another imbalance.  I had intended to add more weight inside the cabs, and then re-install the springs, but I went on a bit of a tear adding crews to all of my locomotive cabs.  The weights likely would have served as seats for the surgically modified engineer and fireman, but they'd then block access fror the screwdriver needed to remove the cab if the loco needed to be disassembled. 

Wayne

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Posted by Attuvian on Thursday, September 13, 2018 11:52 PM

peahrens

c) leading and trailing trucks.  If the trucks had much stronger springs than needed to barely help them track adequately, they would be stealing weight (downforce) from the driven axles / wheels and reduce traction.

Paul,

In his presentation on Bluetrain, Wayne did mention that in doing his mods he had to replace trailing truck springs which effectively skewed the driver pressures so that they were unequal for each axle.  With all the variables, not to mention the available spaces present in the boiler for additional weighting, it is all an exacting exercise in the art of physics.  A few of us become as capable as violin makers, but most of us do well to rise to less exacting results  I can see why many throw up their hands and just consign wimpy locos to flatlander or short consist duties - or get rid of them.  Arrgh.

The issue of traction tires adds a new factor.  The Athearn Mountains have them, but I don't think they're on all four driver axles.

Thanks for your initial observations.  Heady stuff, once one begins to reflect a little.  Mr. Cargo, my junior college physics teacher from the previous century, would have moved you to a seat in the front row of the classroom - where all the smart ones sat.

John

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Posted by doctorwayne on Thursday, September 13, 2018 11:57 PM

peahrens
...if we had a 0-8-0 with center of gravity not over the midpoint of the 4 axles, let's say towards the last axle, the forward axles would lose tractive effort and the rear axles would increase their effort and it would tend to come out near the same. Two caveats come to mind. If the drawbar to the tender started picking up some of the out of balance force, some of the loco weight would transfer to the tender for a net (tractive) loss. If nearly all the weight were over the 4th axle, it would be ok (if that axle not on an especially slippery area)??...

It seems to me that if only one wheelset were bearing the bulk of the weight, then yes, you'd think it would still be okay, but were the weight balanced, the friction of eight wheels would, I think, translate to more applied tractive effort.

Given relatively equal specifications an 0-8-0 was generally more capable than a comparable 0-6-0.
 

Wayne

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Posted by Attuvian on Friday, September 14, 2018 12:11 AM

doctorwayne

 . . . the loco is fully assembled for the balance test, even though the lead and trailing trucks have little weight to contribute and are mostly supported on their own wheels.

As Ed mentions, you can create a balance with a piece of wood and some dowel - I made mine from a sheet of brass, with heavy brass wire soldered across its balance point . . . 

Wayne

Thanks, Wayne.  And Ed, too.  I get the notion that merely establishing a pivot at the mid-point of the driver wheel base is sufficient and that I should not concern myself with the possibility of loading variations from one axle to another.

But I'm inclined to think that any platform upon which the engine is placed for the test must extend equal distances from the mid-point of the drivers' wheelbase.  If not, I would think the platform itself will be unbalanced and throw the whole test out the window.

John

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Posted by Attuvian on Friday, September 14, 2018 12:20 AM

doctorwayne
. . ., the friction of eight wheels would, I think, translate to more applied tractive effort.

Given relatively equal specifications an 0-8-0 was generally more capable than a comparable 0-6-0.

Wayne

 
I'd certainly buy that.  Intuitively, eight points where a given coefficient of friction can be applied to the rails is better than six.  Presuming that the per axle load weight for four is the same as for three . . .
 
John
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Posted by doctorwayne on Friday, September 14, 2018 12:50 AM

Attuvian
....I'm inclined to think that any platform upon which the engine is placed for the test must extend equal distances from the mid-point of the drivers' wheelbase. If not, I would think the platform itself will be unbalanced and throw the whole test out the window.

Yes, the balance platform, by name and nature, is of course balanced when not in use. 
If you put a loco, balanced at the mid-point of its driver wheelbase, with that mid-point atop the fulcrum of the balance, it matters not if the loco's pilot extends further from the pivot point than does the rear of the cab - the balance is for weight only, not length.
Properly balanced, everything forward of the mid-point of the driver wheelbase weighs the same as everything aft of that mid-point.

This one was harder to balance than any of my other steamers...

....and still isn't all that great for moving much of anything.  I had intended to use it as a pusher on the long grade up to the layout's second level, but I added all-wheel pick-up to both tenders, which creates too much drag.  On a positive note, it can run a fair amount of distance into an unpowered siding, though.

Steam pipes are lead-filled tubing...

...as are the air tanks under the running boards...

...and those atop the boiler, too...

...and both engines have lead weights atop their respective gearboxes...

...and in the sand domes and top of the smokebox, too...

Wayne

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Posted by Attuvian on Friday, September 14, 2018 1:05 AM

Holy smokers, Wayne. If there is an available space, it gets loaded with lead. Have you registered any of your locos as potential deadly weapons?

Whistling

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Posted by Attuvian on Friday, September 14, 2018 1:13 AM

doctorwayne

...as are the air tanks under the running boards...

Wayne

 

What are the gizzies hanging beside the firebox like so many stored fishing floats?

John

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Posted by doctorwayne on Friday, September 14, 2018 1:17 AM

Those are known as overfire jets...they used steam to force more air into the firebox.  I'm not sure if it was only to improve loco performance or also an attempt to control smoke from the stack.

Wayne

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Posted by Attuvian on Friday, September 14, 2018 1:54 AM

doctorwayne

Those are known as overfire jets...they used steam to force more air into the firebox.  I'm not sure if it was only to improve loco performance or also an attempt to control smoke from the stack.

Wayne

 
Both sides, I presume.  Coal burners only?
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Posted by doctorwayne on Friday, September 14, 2018 2:45 AM

Yup, both sides...

From the photos I could find of locos with overfire jets, all were coal burners.

Wayne

 

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Posted by 7j43k on Friday, September 14, 2018 9:45 AM

Attuvian

But I'm inclined to think that any platform upon which the engine is placed for the test must extend equal distances from the mid-point of the drivers' wheelbase.  If not, I would think the platform itself will be unbalanced and throw the whole test out the window. 

 

This is an important point, if you're using this method.  You are balancing BOTH the locomotive and the platform.

During setup, put only the platform on the dowel and balance it.  Make a mark on the platform for this point.  Since the platform is almost surely of equal cross-section on its length, the middle of the platform will be the balance point of the platform.

When you place the locomotive (no tender, by the way) on it and balance the assembly, the mark on the platform will have to line up with the dowel.  You essentially move the loco on the platform to find ITS balance point.

 

 

I think Paul is right about the balance point being anywhere within the driver wheelbase, but only as a first approximation.  If nothing else, having it too far from the middle might encourage derailment tendencies on the light end.

Wayne mentioned placing a saddle of lead over an engine.  An experimentalist might used this technique to determine how important centering the balance point is--just reposition the lead and see if it makes a difference.

 

 

Ed

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Posted by peahrens on Friday, September 14, 2018 10:12 AM

doctorwayne

 

 
peahrens
...if we had a 0-8-0 with center of gravity not over the midpoint of the 4 axles, let's say towards the last axle, the forward axles would lose tractive effort and the rear axles would increase their effort and it would tend to come out near the same. Two caveats come to mind. If the drawbar to the tender started picking up some of the out of balance force, some of the loco weight would transfer to the tender for a net (tractive) loss. If nearly all the weight were over the 4th axle, it would be ok (if that axle not on an especially slippery area)??...

 

It seems to me that if only one wheelset were bearing the bulk of the weight, then yes, you'd think it would still be okay, but were the weight balanced, the friction of eight wheels would, I think, translate to more applied tractive effort.

Given relatively equal specifications an 0-8-0 was generally more capable than a comparable 0-6-0.
 

Wayne

 

First and foremost, Wayne, your modeling is incredible and your very complete (with photos) make it most interesting.  Maybe in my next lifetime...

If I may, I find exploring the traction issue a bit more of interest, so read on or ignore as you may be interested in that angle.  Purely for interest...

I've reinforced my conclusion that the center of gravity being within the (driver axles / wheelbase is a critical issue, but off-center within that wheelbase is not a significant issue from a traction angle.  

The key thing is the equation (see link above) where tangential friction force (traction at a wheel rim) equals, and is proportional to, only two things:

1. The "normal" (vertical) downforce (weight) applied at the wheel rim / rail interface

2.  The "coefficient of friction" for that type interface.

Per Wiki, a USRA 0-6-0 had a loco weight of 165,000 lbs (27,500 lbs per wheel) and a tractive effort of 39,100 lbs.  That divides to a design coefficient of friction of 0.237.  The tractive effort (friction force) is 39,100 / 6 = 6,517 lbs force per wheel (assuming equal weight on each).  Using this example, if the mid axle were too high and those 2 wheels suspended, the 165,000 lbs downforce would be on 4 wheels, or 41,250 lbs per wheel.  Each wheel would provide 41,250 x 0.237 = 9,776 lbs force tractive effort, the weight on the rim times the coefficient of friction (a characteristic of the rim steel against the railhead steel).  The 4 wheels would provide 9,776 x 4 = 39,104 lbs tractive effort in total.  Assuming the loco can provide enought HP to get the wheels to the point of slip beginning, where static friction force is exceeded and slip begins.  (Then you get into dynamic friction, where the coefficient is different.....). 

One might find this counterintuitive in some ways.  For instance, with more weight on each of the 4 wheels in contact with the rail, the rail may deform more and create a larger contact area.  But as long as the coefficient of friction charactistic of the wheel rim and rail is what it is, the area of contact is not in the equation.  The maximum tractive force is only proportional to the weight appied to the contact area and the coefficient of friction.

Similarly, a USRA 0-8-0 had a loco weight of 220,000 lbs and tractive effort of 51,042 lbs, computing to a 0.232 design coefficient of friction.  If one (or two) of its pairs of wheels were suspended, the 6 (or 4) remaining wheels would compute to the same total 51,042 lbs tractive effort.  I conclude that the idea of the 0-8-0 was more tractive effort (than the 0-6-0) desired, which with the typical (constant) coefficient of friction, meant a proportionally heavier loco was required to create proportionally more traction (no matter how many drivers).   

Which got me wondering why 0-8-0's were developed.  Why not make a 0-6-0 (or 0-4-0) that weighed the 0-8-0's 220,000 lbs?  I presume there were several reasons, perhaps rail capability per wheel, or weight per axle bearing, wheel rim wear affected by weight, etc.  

For any that have read this far, I've found it an interesting refresh plus learning experience.  Hopefully not too boring.  Mr. Gralla, Madison H.S. physics teacher, not only last century but also last millenium(!) would be proud.

Paul

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Posted by garya on Friday, September 14, 2018 11:16 AM

doctorwayne

Even if the loco is picked up, with thumb and finger on the running boards in a light grip, and at the mid-point of the driver wheelbase, you can get a pretty-good sense of how well it is (or isn't) balanced.

Prior to doing the modifications outlined in that thread, I placed one of those locos and its tender on the layout, then draped a "saddle" of folded sheet lead over the boiler, and while restraining the tender with my hand, applied power.

The locomotive attempted to surge forward, then immediately slipped its drivers, a sure sign that the weight was not too much for the motor to handle.  As I recall, that "saddle" was well in excess of two pounds, and of more volume than could ever be fit into that locomotive.

The Athearn USRA locos (Mikados and Pacifics) both came with springs on the trailing truck, and I think that its main purpose was an attempt to shift some of the imbalanced weight forward. 

 

I have an Athearn Genesis Mikado, and it seems to balance over the third driver.  It has issues--it seems to short out on Atlas turnouts near the frog.  I ran it on my friend's layout, which uses Peco track and turnouts, last night and while it didn't short out, it seemed to have problems having all the drivers staying on the rails--it looked like the second driver was "off" the rail.  I wasn't derailed, but I couldn't get all the drivers to sit flat on the railhead.

I have to admit I'm a little afraid of performing the surgery the good Doctor prescribes--I'll start by adding some lead weight to the front end to see if it helps.  But I may have to break down and start cutting.

Gary
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Posted by doctorwayne on Friday, September 14, 2018 12:45 PM

garya
...it seems to short out on Atlas turnouts near the frog...

I'm guessing that rather than a short, what's happening is that the loco is losing contact with the track.  I had a number of Atlas turnouts which worked well with all of my Athearn Mikes (I did mention, but perhaps only in the linked-to thread, that I added Bachmann pick-ups to the tender trucks on my Athearn Mikes), but when a visiting friend brought several brass locomotives to run (Mikes, Mountains, and Northerns), all of those locos stalled on the same turnouts.

It seemed unusual that all of those locomotives would have the same problem, so I looked to the turnouts for the problem.
What I found was that some code 83 #6 Atlas turnouts had frogs that were too high.  The brass locomotives, with their usually too-stiff springing, and at low speed, ended up with the non-insulated drivers on the unpowered frog, and none on that side in contact with the live rail before or after the frog.
In contrast, the softer springing in the Athearn locomotive allowed the wheels to move up and down as they should, and at least one wheel would be receiving power as the loco passed over the frog.  Even if the Athearn loco was sprung like the brass ones, the fact that the tender collected power from both rails (one truck for each rail) allowed it to continue without hesitation.

After my friend had left, I checked all of the Atlas turnouts by placing a metal straightedge across the rails (power off, of course) and sliding it along the railtops to the frog.  Any which revealed the frog to be too high were quickly remedied with judicious use of a mill file. (Based on the placement of the turnouts, it appears that all offending ones were purchased at the same time, and likely from the same production run).

If some drivers aren't contacting the rail, check that the wheel wipers aren't mis-bent and somehow causing the problem.  The drivers are sprung, but it's a bit more of a job to get at them, and I doubt that the problem would be there.

Wayne

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Posted by snjroy on Friday, September 14, 2018 1:24 PM

If you are dealing with DCC, a short would likely cause a system shutdown, while a contact problem would not cause a total shutdown. I recently had a contact problem with a Mantua 2-8-4. I fixed the problem by adding a keep-alive decoder. They really do wonders to prevent that contact problem, in DCC mode of course.

Simon

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Posted by doctorwayne on Friday, September 14, 2018 2:18 PM

peahrens
...For any that have read this far, I've found it an interesting refresh plus learning experience. Hopefully not too boring....

I read it all and did find it interesting and informative, and not at all boring.  I am, however, not scientifically-minded at all, so am not really qualified to dispute your conclusions. 
All I know is that my two purchased-new Athearn Mikes were useless pullers and the modifications made changed them into useful locomotives, capable, when doubleheaded, of handling a 100oz. train on my long 2.8% grades. 
The improvements lead me to purchase four more of them, all only slightly used, likely due to their poor performance. 
Two of those are in-service, while the other two await conversion to change their appearance to match a couple of different prototypes, but they'll also get the performance upgrades.
A pair of my slightly modified Bachmann Consolidations could handle that same train, but I had mistakenly thought that I had at least changed the plastic air reservoirs for lead-filled brass tubing.  I finally got curious enough to check, and was surprised to find the plastic ones still in place, but not for long...

I didn't bother modifying the stock weight in the same way as on the Athearn locos, but did add weight on the frames, inside the domes, smokebox front, and air reservoirs, and on the cab floor and in the cab ceiling. 
Weight now, loco only, is about 16.25oz., with five such locos in service.  I have another three awaiting conversion to match specific prototypes, but hope to get them at least to a similar, if not higher, weight.

Wayne

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Posted by Attuvian on Friday, September 14, 2018 3:46 PM
Visual proof of Dr. Wayne's workbench mass production facility. Economy of scale lives!
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Posted by doctorwayne on Friday, September 14, 2018 4:25 PM

Thanks for your comment, John, but the multiple locomotives (or freight cars passenger cars, or structures) all identical or almost so, are my method of dealing with repetitive tasks which can quickly become boring.  If I figure out how to do something previously unfamiliar to me, I'd rather make that improvement or use that new idea to complete all, or at least as many as I feel will ever be needed, in one project.  Returning years later to recreate something I've built in the past is difficult...partly because I may have forgotten some of the process, but more likely it's even more boring the second time around.  The enjoyment is, for me, in figuring out how to do something, and then completing it.

A friend had often commented on my scratchbuilt scale test cars, and was lamenting the fact that the Walthers ones weren't currently available, and that mine looked so nice.  Always a sucker for a compliment, I commented that if I had a suitable truck to build it on, I could make him one.

Well, wouldn't you know it, but he comes up with a somewhat suitable truck.  I wasn't totally enamoured of the truck, though, and since I was busy with other projects, was able to put it off for a while.  I don't recall where, but I finally found a single, more suitable truck.  Out of excuses, I inspected one of my earlier builds (one of five built at the time, with two going to other friends - the current friend was unknown to me at the time), trying to recall how I had constructed them.
Here's one of mine, at the tail end of a train...

Once I figured it out, the project was done fairly quickly, but the latest one is, I think, better done than the originals....I guess that my skills must have improved, but how long before I decide that my scale cars need upgrading? Bang HeadSmile, Wink & Grin

Wayne

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Posted by peahrens on Friday, September 14, 2018 5:04 PM

doctorwayne
All I know is that my two purchased-new Athearn Mikes were useless pullers and the modifications made changed them into useful locomotives, capable, when doubleheaded, of handling a 100oz. train on my long 2.8% grades. The improvements lead me to purchase four more of them, all only slightly used, likely due to their poor performance.

Wayne, this triggers some final technical thoughts on weight, balance, etc:

1.  As long as the center of gravity is within the driver axles, the loco does not (on level track) have a tendency of "tilt" towards the pilot or cab, so ALL added weight must fall only upon the drivers (which is good, of course).  The reason is that the lead and trailing trucks only have a downward force of the truck weight plus its spring force (when compressed partially on level track).  Added weight portions can not transfer to the lead or trailing truck as those wheels see only their weight and that truck's spring force, which is constant as it is compressed the same before and after.  (Ignoring if any driver springs compress more, which creates a secondary effect in theory by compressing the truck springs a bit more.)  Back to the main point, your Mike's traction after weight addition should be essentially (16.75 oz. / 12.5 oz. ) x 100 = 134% of original, which is significant for performance, as we know, and quite impressive given the severe limitations on room to add weight.  One could enhance the precision of this calculation by looking at the weight on the drivers only (before & after), subtracting the trucks' weight and spring compression force on same, but that might increase the % improvement by only 1% or so.

2. You can add to that improvement, if were known, the amount of gross weight transferred to the drivers by removing the trailing truck spring, which was "stealing" (by supporting) some of the loco gross weight from the drivers, keeping them from maximum (no sprung trucks) potential traction.  All in all, you are probably in the 35-40% traction improvement zone.

As Forrest Gump said" "And that's all I have to say about that".  Enough.  If you ask my kids, they may advise that I can get a bit nerdy.  I enjoyed the thought process.  

And again, your work is most enjoyable to see (and envy).  Have you / do you contribute to MR magazine?  That would steal some of your valuable time, but I'm not convinced that everything shown is your work alone.  I'm thinking there may be several dozen talented elves cranking out at least some of your projects.

Paul

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Posted by Attuvian on Friday, September 14, 2018 7:45 PM

peahrens
. . . . I can get a bit nerdy.  I enjoyed the thought process.  

And again, your work is most enjoyable to see (and envy).  Have you / do you contribute to MR magazine?  That would steal some of your valuable time, but I'm not convinced that everything shown is your work alone.  I'm thinking there may be several dozen talented elves cranking out at least some of your projects.

 

Paul,

Like Wayne, I have been able to follow along and have found your "nerdy" offerings to be insightful and thought-provoking.  Once again, kids have no clue - it generally dawns on them later, when we're either already chilling underground or too addled to be able to say, "I told you so!"

As for Wayne's "elves", I'm begrudgingly thinking they don't exist at all.  I'm willing to bet that we have in him a prime example of the guy who 1) knows his tools (and where they are), 2) has used them constantly for many years, 3) whose fingers are as fast as his mind and, 4) has stored up in that mind a huge reservoir of creative techniques and shortcuts born of what's worked and what hasn't.  Yeah, I can build a bookcase from scratch in my garage.  But it will take me four times as long (and won't look as good) as the identical one an old friend of mine could whip up seemingly out of his back pocket.  He's accomplished in it, and I'm not so much - yet.  It's that perfect marriage of capacity and experience that we all admire and strive for.  The real blessing is that Wayne and those like him offer it up to us all so freely.

It is one of the richest rewards offered by this hobby.  And it is also transferrable to a whole host of endeavors in other areas of life.  Just another reason why we all ought to make extra efforts to get younger folks into this business.  It's a lesson that I'm suspicious is not as prevalent elsewhere at it used to be.  And a lesson that enables folks to become more than they might otherwise have thought they could be.

Hadn't intended to be so reflective.  And apologies to those that have found this perhaps a bit tedious.  I'm just being grateful for having found in this hobby far more than I ever expected.

John

 

 

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Posted by doctorwayne on Friday, September 14, 2018 10:30 PM

Those of us who have something to share get at least as much from that sharing as the person who learns something new from it.  And I think that all of us can learn new things, whether from long-time modellers or those just starting out.  Isn't the point of places like this to be an exchange of ideas?

peahrens
.....Have you / do you contribute to MR magazine? That would steal some of your valuable time...

Only once, Paul, and yes, it was, at least for me, time consuming.  It was a Paint Shop article, on how to paint and letter diesels for prototypes which, at that time, there was no suitable lettering available.  It involved painting (with a brush in those days) in the lettering colour, then applying dry transfer lettering (from alphabet sets) over that as masking devices, then applying what would become the background paint once the dry transfers were removed.  That use of dry transfers wasn't my idea - I owe Art Curren my gratitude for an article he wrote on creating multi-coloured signs.  My small contribution merely substituted locomotives for the signs. 
I sorta doubt that many folks read the article, then actually applied the method to whatever model they wished to create, and that was borne out by the fact that I did about 70 locos in the same paint scheme for modellers who frequented a local hobbyshop where I had left the locos on display for a couple of weeks (at the request of the store's owner).
The models, Athearn geeps, needed removal of the dynamic brake detail and of the steam generator details for freight units, and the paint job was labour intensive: two colours applied with a brush, then lettering and striping with dry transfers, then the same two colours, again applied with a brush, but over the opposite colours.  The dry transfers were then removed to reveal the contrasting painted-on lettering and striping.  However, at that time, there was no dry transfer for the herald on the cabs' sides, so I did them free-hand, with a brush...



I started out charging $25.00 per unit, but continued to bump that up as there appeared to be no abatement in orders...I wanted to discourage buyers, to be honest, as the work was labour intensive, and when I eventually switched to an airbrush, I suddenly discovered that I had to mask for colour separations, something not necessary for brush work.

Another view of one of my original brush-painted ones...

...and one of the slides used in the article...

...and one of the real ones...


I had no idea what painters would have been charging at that time, and no one seemed to be willing to share that info.  I later learned that even at its highest, my prices were more than 50% less than most were charging for very simple one-colour schemes, with readily available decal lettering.
The bright side of that experience was meeting a couple of modellers who became good friends, and still remain so almost 40 years later.

I painted, mostly brass, for them for many years at very reasonable prices, and it only dawned on me later that I was charging my friends for the privilege of painting for them. One is currently out of the hobby, but I still paint for the other, and the friendship of both is worth more money than anyone could ever offer.

Eventually, Atlas did this paint scheme on their HO geeps, and LifeLike Canada later came out with very nicely-rendered version, too.  I was relieved!

Sharing info here, while not as lucrative as writing articles, is a lot easier, and adding pictures not at all demanding of perfect exposures. 
I also think that the audience here can get the info they want almost "on-demand", and in return, those providing the info get responses back just as easily. 
Some of the latter are favourable, some not so much, and others offer alternatives, which, as I mentioned earlier, is an opportunity for all of us to learn more.

My apologies for going on (as usual) at such length, but I felt that the previous posts deserved an in-depth reply.

Wayne

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Posted by NWP SWP on Friday, September 14, 2018 11:59 PM

I'm considering purchasing an old AHM/Rivarossi Big Boy adding elephant ears and swapping the tender for two Santa Fe 52' oil tenders, I'd have to change some details on the locomotive to make it an oil burner.

I didn't know that steamers had to be balanced, quartered yes, balanced no.

Steven

Crooner, Imagineer, High School Graduate, living with Aspergers, President of the Republica Pacifica micronation,  President of the NWP-SWP System.

Hook'em Longhorns! 

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Posted by gregc on Saturday, September 15, 2018 7:56 AM

i'd be interested to hear if rebalancing makes an improvement beyond that of simply adding weight.

I was surprised to read that tractive force is a function of adhesion and a value of 25% of weight on the dirvers is a common reference point.   This varies with conditions -- wetness of the rails.

This page for Reading Company locomotives provides weight on each driver axle.   These were of interest to me

B8a     49412 46675 58038
D8a     47575 48850
I5a     41025 37447 32404 29309
I10sa   70910 71510 71580 70190

I thought it was interesting that the earlier locos weren't as balanced, 40%, as the later (e.g. I10), < 2%.

So I'd be interested in hearing if distributing the weight on a model makes a noticable improvement.   I agree that as soon as one wheel starts slipping, the load on the other wheels go up making it more likely for them to slip.

greg - Philadelphia & Reading / Reading

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Posted by 7j43k on Saturday, September 15, 2018 11:35 AM

gregc

 

This page for Reading Company locomotives provides weight on each driver axle.   These were of interest to me

B8a     49412 46675 58038
D8a     47575 48850
I5a     41025 37447 32404 29309
I10sa   70910 71510 71580 70190

I thought it was interesting that the earlier locos weren't as balanced, 40%, as the later (e.g. I10), < 2%.

 

The weight balancing of real steam locomotives was (and is) much more sophisticated than for models.  So comparing the two is not a one for one thing.

For a real steam locomotive, all wheels are fully equalized.  That includes leading and trailing truck wheels.  Which means that, if you push up on one wheel, it has an effect on all the others.  Rather than just lifting the locomotive up in the air, with all the weight on the lift-point.

That seems to imply that the weight on all the wheels should then be the same--the term "equalized" sort of implies it.  But by changing the lengths of the equalizing arms, you can change the weight ratios on the wheels.  I suspect that accounts for the variations in the Reading numbers.  Whether it was "on purpose" or accidental, I can't say.

 

 

So I'd be interested in hearing if distributing the weight on a model makes a noticable improvement.   I agree that as soon as one wheel starts slipping, the load on the other wheels go up making it more likely for them to slip.

 

 
They won't slip if they are all connected with side rods or drive shaft linkage (on a model).  
 
Now, perhaps you're talking about what I think of as micro-slipping.  That's when slippage occurs and the linkage is sloppy.  As it is on most models.  Interesting.
 
Ed
 
 
 
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Posted by doctorwayne on Saturday, September 15, 2018 2:08 PM

gregc
I'd be interested to hear if rebalancing makes an improvement beyond that of simply adding weight....



If you don't add weight to balance an imbalanced locomotive, then the only other option to achieve balance would be to remove weight.  With the way steam locomotive models are constructed, probably less easy than adding weight. 

Also, if weight is added in a manner which increases the imbalance, loco performance suffers accordingly.

Wayne

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Posted by gregc on Saturday, September 15, 2018 2:21 PM

it seems that the tractive force, even of a model, is some percentage of it's weight --- adhesion.   Track conditions (wetness) shouldn't vary for models.

so if you weigh the model and measure it's tractive force you can detemine that percentage (~~ 25%)

if you add weight to rebalance, re-measure the tractive force, you can re-calculate the adhesion.   If the percentage goes up up, then I'd say rebalancing made a measurable improvement.

but even if it didn't, there's still greater tractive force.

greg - Philadelphia & Reading / Reading

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