The Curmudgeon Challenge

[altterrain]

In this recent thread - http://www.bachmanntrains.com/home-usa/board/index.php/topic,2097.0.html  my online buddy, Dave Goodson (Curmudgeon  ) posted this -

Advantages of stainless outdoors.
Funny.
Those who complained that aluminum was too silvery, suddenly accept the chrome glare of stainless.

Tractive effort alone would cause me to NOT use stainless.

If I can haul 28-34 loads consistently up 150' of 4% with ONE Bachmann Shay, I sure would like to hear what folks with Stainless are able to do.

I guarantee I will out-pull you.

Wire.
Clamps.
Power districts.

Oh, well, now Piko has Brass, and KGB is bringng back the ex-LGB track line, so brass won't be a supply issue....just bring lots of cash.

Well, I thought to myself,  this is a bit of no brainer. You really could not compare any track that has not been cleaned in 20 years, having the texture of sandpaper, to any track that is cleaned on a regular basis. Being a former scientist, I could not resist the challenge. I normally do not run trains longer than 10 cars, so I set out to the backyard (where its 96 degrees in the shade  )) to do a bit of experimenting.
I do run Aristo stainless but my steepest grade is only about 3%. I do not have a Shay but my Dunkirk uses the diecast Shay trucks. So I got out all my scale appropriate rolling stock (we know Dave has a thing about scale) and loaded up the Dunkirk with an additional 3 pounds of lead fishing weights. It has a pound in a half in it but not nearly the weight of a Shay equipped with batteries.




This is the maximum train I was able to pull up my 3% grade with the weighted Dunkirk before wheel slippage -






It consists of 20 cars with 9 box and reefers including the first equipped with battery/RC set up, 1 Bachmann tanker, 2 Aristo 20' cars, 2 flat cars with real, heavy logs, 5 AristoClassic hoppers and a logging caboose. All are equipped with standard metal wheels (mostly SanVal).








So here is my challenge - If you have a Shay (or similar), stainless track and some decent grades let's see what you can do. Go out and do your own experiment and post some pics or video here. The winner (by my judging) will receive one of my Cub.., er, Canadian "pieces of artwork" (at least that's what the shipping box said) recently procured for upcoming vacation.

-Brian

[Curmudgeon]

As long as you understand up front I have no idea what the actual limit is.
My couplers will literally climb out of each other with much more load.
My cars have, oh, 70-80% metal wheels, mix of all sorts of cars, at 34 loads up 150' of continuous (but not exact) 4%, no wheel slip.
Some places have a 5+% grade, nothing less than 4%.

I could grab a box of paperclips, tie the couplers together, and I'd probably get 45 cars up the grade.

When the wheel plating goes away, and you're into the copper (or pot metal), on rough, uncleaned aluminum, you would be surprised at what you can pull.

[gbbari]

Dave have you replaced any part of the Shay's drive train with metal?  What you are also implying in your claim is that the drive train is holding up under this very heavy load.  If yours are still B'mann original, that is quite encouraging for Shay owners like me who have not (and probably won't or can't) put their engines to that kind of test.  But it speaks well of the Spectrum Shay drive train to greater longevity under lighter load conditions (all else being equal).

-GB

[Curmudgeon]

Radio, batteries, no sound, stock plastic housing trucks.
Lead weight in tender removed.
The moving parts on the outside are ONLY driven from the #2 axle, have no stress on them.
This Shay is from the first shipment into TrainWorld what, 11+ years ago?
I got one of the first, been R/C since two weeks after I got it.
Oh, wait, has Trackside Details cast brass pilot step supports.

[Kevin Strong]

... When the wheel plating goes away, and you're into the copper (or pot metal), on rough, uncleaned aluminum, you would be surprised at what you can pull...

Well, yeah. But that's like saying you can accelerate quicker on dry pavement vs. wet pavement. To properly test the factor of adhesion for various rail materials, they need to be cleaned to similar/identical standards. Then--and only then--can you truly say which one allows for better traction.

It should be noted that reducing the potential for wheel slip isn't necessarily a good thing. Wheel slip is what keeps gears from stripping when the load on the locomotive gets to be too much. As prone to gear problems as our locomotives are, it's probably not the best course of action to purposefully eliminate the one safety valve we have against that. Also, while rough track may increase traction, it also increases drag. To what extent these two cancel each other out has far too many variables to accurately calculate, but it's something to keep in mind.

Lastly, it's largely the case that our model locomotives are capable of pulling a far longer train on far steeper grades than their full-size counterparts could ever dream of pulling. While this is certainly a worthy competition, in terms of prototype operation it's over the top.

Later,

K

[Curmudgeon]

The locomotives still slip long before the Mabuchi motors fail.
We have just optimized performance (and not added lead weights all over the loco to get 10 cars around).
We have been trying since day one to kill a gearbox in a 2-8-0.
No luck yet.

The only things we make heavier are 4-6-0's with any BBT chassis, as the combination of aluminum frame, stainless axles, ball bearings and Pittman motor allows 10 pounds more lead.

Been doing this just over two weeks now, Kevin.
Works, and no slippery rails, either.

[Kevin Strong]

The locomotives still slip long before the Mabuchi motors fail.

I'm not talking about motor failure, I'm talking about gear failure. The Mabuchi motors are quite robust little beasts. I've personally never had one fail on me. It's the gears that give us fits, either stripping or splitting on the axles. I know you're not telling me you've never seen a gear split or strip due to excessive load. I've had plenty--and not just from stalling. Slipping and just simple heavy loads take their toll on gears.

Been doing this just over two weeks now, Kevin.
Works, and no slippery rails, either.

Again, you misinterpret my statement. I'm not saying wheels don't slip on rough track. Of course they slip. Dad's aluminum rail is every bit as rough as yours, and we routinely slip wheels on it--especially on the 15' section of 8% grade. But the greater friction means the potential for stalling is greater--especially when you have long trains, heavy locos, and/or locos with such silly things as traction tires. That added stress between the motor trying to turn the wheels and the wheels not wanting to turn gets caught in the gearing. If the gearing isn't up to the stress, bad things happen.

Case in point: The helper loco that pushes trains up the 5 - 8% connecting line on dad's railroad is a 1st generation Big Hauler. Shortly after placing it in its dedicated role as "helper," I split the main gear. Why? Because the plastic wheels wouldn't slip on the rough track. I replaced the gear, and fitted metal drivers on the axles. The wheels now slip when necessary, and it hasn't had a single problem since in well over 15 years. 

Slipping = good (though still to be avoided if possible)
Stalling = bad
Increasing the load on a locomotive to approach the point of a stall = flirting with disaster
Knowing where that line is and not crossing it = mark of a skilled engineer

Knowing that a prototype 2-6-0 would never be able to pull 40 cars up a 4% grade = never worrying about stripping a gear.

Later,

K

[Curmudgeon]

And, you're quoting out of context.
Wheels slip.
Gears are not the issue on stalling.
Motors are.
Not sure what Mechanical Engineering School you got your degree from.

Gears are wear and shock impact items in this application.
Which is why I said we've been trying since what, 2001 to kill the geartrains in our 2-8-0's.


Personally, can't recall losing a Shay gear on one of mine.
EVERY ONE I have had to fix for others has split.
That's a plastics issue, can do it on the shelf having never turned a wheel.

Not exactly sure what you are trying to do here.
I know what I am doing.
I run these to see what happens.
I figure if I can run these in the service I do with no failures, it will run even longer in lighter service.

We have, in fact, loaded Anniversaries down with more weight to remove the machine-gun break-away of the drivers, and loaded the motors to stall.

Didn't continue to failure, just replaced the chassis with a BBT unit.

I went back and looked, nowhere do I advocate in this thread adding weight.
I do believe I mentioned I removed weight.

So, since the wheels still break away, I have had no issues, and the discussion in this thread is a challenge on stainless, I am getting a bit puzzled about your comments.

You have empirical data to support gear failure due to optimized tractive adhesion?

[Kevin Strong]

And, you're quoting out of context.
Wheels slip.
Gears are not the issue on stalling.
Motors are.
Not sure what Mechanical Engineering School you got your degree from.

Gears are wear and shock impact items in this application.
Which is why I said we've been trying since what, 2001 to kill the geartrains in our 2-8-0's.

Dave, we're saying the same thing. It's a system--from motor to gears to wheels. When a motor stalls, it's because the force exerted on the armature by the magnets can't overcome the force being exerted on it by the wheels it's ultimately connected to. The gears are--as you say--shock and impact items, which is exactly the point I'm making. They take the brunt of the push/shove match between the motor and the wheels.

When such a stall occurs, if the gear train is robust, nothing happens. The teeth press against each other, but nothing fails. If it is not, then that's when damage is likely to occur, either by shearing teeth, spinning on the axles, or splitting. There are any number of places along the line where a failure may occur. All it takes is for the torque applied to be greater than what's holding things in the right places.

Bachmann has done a great job continuing to upgrade its drivetrain so it is robust enough to be able to withstand the extreme forces put on the system by a stall. Didn't used to be that way, as you and I both know.

Oh--4 years studying engineering and mechanics in high school, followed by 2 years ME at Univ. of MD before I decided I'd rather take pictures for a living. You may not want to drive over a bridge I design, but I do understand the physics and engineering of a motor and gear system. I've been playing with those since I was still in grade school.

Personally, can't recall losing a Shay gear on one of mine.
EVERY ONE I have had to fix for others has split.
That's a plastics issue, can do it on the shelf having never turned a wheel.

Not arguing that--my Shay came with three broken gears without turning a wheel. But knowing there's an inherent weakness in a system dictates caution when pushing it, or correcting the probelm to begin with--as you do when you fix others' locos.

Not exactly sure what you are trying to do here.
I know what I am doing.
I run these to see what happens.
I figure if I can run these in the service I do with no failures, it will run even longer in lighter service.

Well, it's obvious that you're not sure what I'm saying. Otherwise you'd see that I'm in no way suggesting that you don't know what you're doing.

I get what you're doing, and I completely agree with it. (Read my last post - "knowing where the line is and not crossing it...")

I'm pointing out a very simple way to tell where the line is. For example, how do you know when you've tightened a screw too much? When it breaks. How do you know when a locomotive is too heavy? When the wheels no longer slip when the loco hits an obstruction. The surface of the rails is a factor in determining what that weight would be. (Hence my example of my old Big Hauler with the plastic vs. metal wheels. Same weight, different coefficient of friction between wheel tread and rail.)

I went back and looked, nowhere do I advocate in this thread adding weight.
I do believe I mentioned I removed weight.

You didn't say anything about adding weight. (nor did I allude to you doing so, if you read that in somewhere). I'm the one who mentioned adding weight, as it's the most common method of increasing tractive effort. Lots of locos come from the factory "underweight"--even expensive brass locos. If a Bachmann 2-8-0 outpulls a K-37, it's time to add weight to the K...

So, since the wheels still break away, I have had no issues, and the discussion in this thread is a challenge on stainless, I am getting a bit puzzled about your comments.

My initial comments were relative to your assertion that you could pull a longer train on dirty aluminum track than on smooth stainless, which is a very obvious statement. My comment was that if you wanted to fairly test just the factor of adhesion of both materials, then they should be prepared as close to identical as possible. (i.e., polished or scuffed equally.) Then, you can see how they compare. Otherwise, you're comparing asphalt to ice.

You have empirical data to support gear failure due to optimized tractive adhesion?

Well, no, because what I'm saying is exactly the opposite. Going back to my Big Hauler example--the gear failed because tractive effort was NOT optimized. With plastic wheels on aluminum track, the weight of the locomotive was sufficient keep the wheels from slipping when it hit an obstruction. (eg, the train it was helping up the hill stopped suddenly) This created a stress along the drivetrain which it was not able to withstand. Thus, the gear broke.

When I replaced the drivers with metal wheels--without increasing the weight (beyond that of just the metal wheels), the coefficient of frictiction between the steel wheels and aluminum rail was lower, so the wheels slipped when hitting the same obstruction. As such, the weight was optimized and the gear DID NOT break--thus demonstrating that an optimized weight on a locomotive will reduce gear troubles.

Later,

K

[Curmudgeon]

I've seen Anniversaries self-destruct because of wheel slip!
They jack-hammer when they slip, which is more shock load than you would ever want to put on a gear train.

No, we run the track as it is right now.
No tape on the rails.
The "test" is run your railroad as you do, normally, and see.
If your stainless is shiny brite all the time, and my rail is not, I run mine as they are.

You don't clean your stainless, I don't clean my aluminum.

I could take anything and shine it up with a power polisher and it would all slip, but that's not how my rail is.
AT ALL, and you know it!

My railroad runs this way.
Your stainless track-powered (or otherwise) doesn't.

Why spend the money on stainless when this not only is far cheaper but the tractive effort is so much better?

You're asking to change the "rules" to make my rails not "as used".
No dice.

[Kevin Strong]

Dave, no one's suggesting changing the rules. The "challenge" as it has been stated is fine and it will be interesting to see some of the results. But...

Why spend the money on stainless when this (aluminum) not only is far cheaper but the tractive effort is so much better?

(clarification and emphasis mine)

This challenge without any limits on the finish of the rail surface cannot answer the tractive effort question. For a true comparison, finishes must be nearly identical. If there's someone with stainless track that's been down for a few years but never cleaned who responds, then that's probably as close to what you've got in your back yard as we can expect, and will give the best insight into a valid comparison.

I've seen Anniversaries self-destruct because of wheel slip!
They jack-hammer when they slip, which is more shock load than you would ever want to put on a gear train.

You don't mention the condition of the rail when these locos are "self-destructing." If it's anything like my dad's aluminum rail, which is very similar to yours, yeah--slipping locos hop around like little rabbits as they try to gain footing. And the lighter the loco, the more pronounced the hopping. It sounds more like stuttering than slipping. (You refer to it as "machine-gun breakaway," which is very apropos.) Such stuttering could also be due to the finish on the wheels themselves. If it's not polished, it will also have the same tendency to want to bounce.

True, slipping isn't the best for gears, either, and the stuttering does introduce momentary extreme forces on the system that may--in that instant--be greater than those introduced in a simple stall. Both scenarios (slipping and stalling) should be avoided, but slipping--even with the stuttering--is still the lesser of the two evils.

Later,

K

[Curmudgeon]

Unbelievable.

[Kevin Strong]

Unbelievable.

TOC seems to be of the rather mistaken impression that I am championing smooth stainless steel rail, and that rough aluminum track is evil. Nothing of the sort. As I've alluded to in the above posts, my dad's railroad was built with aluminum rail 27 years ago, and it's been at least 22 years since it last saw any kind of cleaning. I'd hazard a guess to say his track may actually be a bit coarser on the surface than TOCs, since it doesn't see the routine use that TOC's does. Save for the one example I mentioned, none of our gear failures we've experienced are directly linked to the track. I used aluminum rail on my line in Rochester, and I would have used it again for my current one if the AMS flex track hadn't been surprisingly cheaper. (I was also hoping the brass would weather naturally, which it is--unfortunately--very slow to do.)

There is nothing unsound about rough (uncleaned) rail of any material. It does provide for greater traction--which when you've got steep grades like my dad and TOC have on their lines is a definite advantage. There is a trade-off, though, in that if you're going to add weight to your locos to improve their performance, you cannot add quite as much weight before the wheels no longer slip on the rails. It's a friction thing.

Technical crap--ignore if you're not a physics geek
If you look at engineering tables showing the coefficients of friction for various materials, it doesn't always hold that harder materials have lower values. For instance, the published coefficient of friction for mild steel on mild steel surfaces is .74 (high amount of friction), while mild steel on aluminum is .61. Steel on copper is .53. Granted, these published numbers don't necessarily translate to the particular alloys used on our trains, but they do provide some interesting food for thought.

Later,

K

P.S. To all those discussing this thread back-channel, GO TO THE SOURCE. No sense speculating what I mean when all you need to do is ask me. Don't rely on interpretations.

[Mark Oles]

Kevin,

I'm following what you are saying.  I wonder how much the rail surface can play in to the original challenge.  If there is more surface roughness on aluminum rail then perhaps yes, the locomotive achieves better adhesion when on grades.  However, I think there will also be more friction from the consist.  If the surface of the stainless is something less than the Aluminum, then there's less adhesion to the rails to pull a train with less wheel rolling resistance.  I think we're splitting some hairs there.  BUT, I don't have any way to verify that with my railroad (built with aristo stainless) since I don't have any aluminum rail.   Sort of like comparing tractive effort of locomotives on dry rail vs wet rail vs wet rail with SAND!

Posted by TOC

If I can haul 28-34 loads consistently up 150' of 4% with ONE Bachmann Shay, I sure would like to hear what folks with Stainless are able to do.

I think this challenge is inherently flawed since the testing has to take place on each individual's railroad. My railroad is built different from TOCs and yours, so how could I compare my pulling power to either?  And what would be the result of  that data?  I believe in the end it would show that on my railroad you could pull XX number of cars, on TOCs, you could pull YY cars, on yours ZZ, etc... I think that each of us, consiously or unconsiously, wants to know the capabilities of our locomotives on our railroads. At some point, I know I do my own load up test on all of my locomotives to see what they can pull on my railroad.  It might be the same as someone else or it might be completely different, and in the end, there's no real way to correlate.  To me, it just seems like there's too many variables at play.  Oh and what's the weight of the cars, etc...

I don't have the same 4% grade for the same distance with the same geometery (curves, etc) for this to be a fair comparison. (Oh yeah, if I had a Shay.)  I have pulled 20 car freights with a single locomotive before.  I've also stripped gears in a LGB mikado (broke at the star drive pulling too long a train) and a LGB Mogul (locomotive derailed #1 driver, got itself in a locked position with the motor still trying to turn.  What gave out? The gear).   The gears are the cheapest thing to replace in the drive train, and accordingly, those are what strips out when the wheels are locked or stalled instead of the motor burning out.

Later,
Mark