[markoles]

For years, whenever anyone mentions track and the debates begin between brass and stainless, TOC sometimes jumps in with his Aluminum track.  I have to admit that I have been dismissive of his claims that Aluminum track has better adhesion characteristics.

In this months GR, there's a story of a high schooler who did a series of test regarding adhesion and he removed the variable of conductivity of the rail by using battery as his power source.  His results show that the Aluminum track has the best overall adhesion.   He had some other results that might warrant further discussion here.

Is humble pie served ala mode?  I'll have vanilla.

Mark

PS If he's right about the track, does that mean he's right about the 49 flat head Fords too?  Oh! the humanity!

 

[Torby]

Annoying how often he's right, isn't it?

 

[Greg Elmassian]

TOC gave me the results of current draw tests on brass vs aluminum on the new K, it was quite different. I was not totally surprised, though because brass rail is often hard and smooth, while aluminum seems to take a "tooth" or "grittier" finish. The resulting difference in adhesion and current draw was dramatic though. If I ran battery only, aluminum would be my choice.

Regards, Greg

 

[Chris France]

I'm not at all surprised i do agree with Greg that aluminum track does not have a poished smooth surface (which I believe they could do if they wanted, but they don't). Just remember that while the increased adhesion does mean the engine has more pulling ability, it also creates more drag on each car in the train, so I wonder if it improves real world car counts as much as you would suspect.

 

[Paul Norton]

 
The brass rail over time will turn a realistic dark brown color, unfortunately aluminum rail will not.

 

[Richard Smith]

Chris,

If the aluminum rail produces any more drag than brass it's not enough to notice. My present fleet of locomotives are all "original" Delton C-16's. If you remember when they first came out many people complained of their lack of pulling power mostly on the then most popular LGB brass track which was also what I used. I can easily pull 12 to 14 Bachmann freight cars on my aluminum track, better by a factor of at least four over the brass on a previous layout. I have even pulled 12 sets of LGB disconnects fully loaded with real solid wood logs, a very heavy train. All this is on fairly level track of course.

To be fair however there is also the fact of my lokies being battery power. I'm not advocating here, just explaining so please bear with me. Since there is no longer a need to clean the rails for good conductivity any small particles of dust and dirt can theoretically help traction much like sanding the rails does for prototype trains. Of course dirt can be a negative too if it's slippery or clumped enough to cause wheels to lift off the rails. Additionally the current flow to the motor is constant via a direct connection by wires from the batteries instead of through partially dirty rails or being interupted because of a dead spot. All of these factors might increase pull power too.

 

[Curmudgeon]

To give you an idea, drawbar pull on a 2-8-0 and the 2-8-2 on old brass is about 2.5 pounds.
On my old aluminum track, it's 4.
Current draw also goes up considerably.
Same engine, same day, same fish scale, attached to the same location on the loco.
On Bachmann older 2-truck Shays, we regularly haul 28-34 loads (did 36 once with no problem) up 150' of 4% unassisted with no wheel slip, once the plating on the tires goes away.
I've been doing this for a while.
Now, on stainless tires, or solid nickle with no plating, maybe not.
But my engines will pull teeth.
And that's no additional weight.

 

[Rod Hayward]

Nah, I just hate it when I'm wrong.....

 

[blackburn49]

Posted By Curmudgeon on 02/29/2008 10:53 AM
To give you an idea, drawbar pull on a 2-8-0 and the 2-8-2 on old brass is about 2.5 pounds.
On my old aluminum track, it's 4.
Current draw also goes up considerably.
Same engine, same day, same fish scale, attached to the same location on the loco.
On Bachmann older 2-truck Shays, we regularly haul 28-34 loads (did 36 once with no problem) up 150' of 4% unassisted with no wheel slip, once the plating on the tires goes away.
I've been doing this for a while.
Now, on stainless tires, or solid nickle with no plating, maybe not.
But my engines will pull teeth.
And that's no additional weight.
This is reassuring to learn considering how much of this aluminum Llagas track I have purchased from you, DG. I must say that it makes sense. The brass track  definitely seems to be relatively slicker while the aluminum seems to have relatively good grip qualities.

 

[Greg Elmassian]

If you want slippery stuff, try stainless steel! It's like greasing the wheels! Of course, since I'm mostly SG, it's just an excuse to cut a helper on, so the more the merrier!

Regards, Greg

 

[pfdx]

Its the hardness of the material. Aluminum is the softest and stainless is the hardest and brass falls in the middle. The softer the rail is in relation to the wheels gives you more adheasion. The same principle was used with steam locomotives, switcher and drag freight engines used a softer grade of tire to give them more pull while passenger and faster freight locomotives had harder tires to stand up to more abuse. The wheel rail material interface is an on going topic is R&D as materials change and harder rail is produce to last longer between grindings but that affects wheel life so the search is for the balance. For the most part the railroads still consider the wheel to be the sacrifical part. Wheels are fast and cheeper to change that the rail.

 

[blackburn49]

Posted By pfdx on 02/29/2008 4:18 PM
Its the hardness of the material. Aluminum is the softest and stainless is the hardest and brass falls in the middle. The softer the rail is in relation to the wheels gives you more adheasion. The same principle was used with steam locomotives, switcher and drag freight engines used a softer grade of tire to give them more pull while passenger and faster freight locomotives had harder tires to stand up to more abuse. The wheel rail material interface is an on going topic is R&D as materials change and harder rail is produce to last longer between grindings but that affects wheel life so the search is for the balance. For the most part the railroads still consider the wheel to be the sacrifical part. Wheels are fast and cheeper to change that the rail.
Great info--not just of our models but the real thing.  Thanks for sharing it.

 

[pdk]

Posted By Paul Norton on 02/29/2008 10:10 AM

 
The brass rail over time will turn a realistic dark brown color, unfortunately aluminum rail will not.



Respectfully, I think you need to put quotation marks around "realistic."

 

[Mike Reilley]

I thought the most "interesting" part of his science project was the wet rails result.  On all but the stainless, the pulling force on the wet rails was 16 to 90 percent HIGHER the other test conditions (room temperature, hot, and cold.  On stainless, tractions stayed about the same.  

Why would engines pull better on wet rail?  That's certainly not like the real thing.

 

[Art]

If you look up the coefficient of friction for the different material you would see that all the testing was in vain. The mathematical methods prove the same point...... Damn seems like we did that type of thing in engineering school... A young kid learned in a few days what took me 4 years to learn....
 
Art

 

[East Broad Top]

Ah, but Art, it was the testing that gave the mathematical coefficients in the first place. Always good to double-check once in a while. Kinda like gravity. I know it's there, but every now and then, I drop something on my toe just to check. One of my favorite scientific exchanges, from the movie "Awakenings."

DR. SAYER
It was an immense project. I was trying to extract a decigram of myelin from four tons of earthworms.

DIRECTOR
(pause) Really.

SAYER
I was on it for five years. I was the only one who really believed in it. The rest of them said it couldn't be done.

KAUFMAN
It can't.

SAYER
Well, I know that now. I proved it.


Besides, coefficients vary based on particular alloys, so what's listed on the tables may or may not be accurate for the exact material on our track.

Later,

K

 

[Dan Pierce]

From the magazine article, my new RR needs to be built with brass track in the bottom of my pool. My pulling power will go way up as the water density will offset the weight of my cars as well as the traction increase of the engine. My stainz will be able to pull 100 cars!!

I must use LGB engines as they are tested in water with no electronics.

My biggest problem will be converting my bubble car to this water soaking method. Perhaps i can just add an air cylinder and pulse the output. Same for the steam engines. Air bubbles instead of smoke.

 

[Rod Hayward]

Nah, mostly i hate it when I am wrong....

 

[Dean Whipple]

As long as I've been reading Dave's posts, and it's been many years (since way before MLS...) I can't remember when he was wrong....

 

[Wendell Hanks]

How about adding your written support to the posting "To Kader Industries: Please read this request," on Ask The Bach-mann site. I, along with many others, are disgusted with the no pre-shippment testing. I encourage all of us to write on the posting our strong request for Kader to pre-shipment test ALL of their large scale locomotives before selling them to the public.

I know Dave has advocated this practice for years and has gotten Bachmann's admission that this is not done.

Kader is the parent company for Bachmann and, according to direct Bachmann sources, uses the Bachmann site as a source for consumer responses.

Here's a chance to clearly, and strongly, advocate a goal for all of us in large scale.

Wendell