# Locomotive Back to Back wheel spacing



## StanleyAmes (Jan 3, 2008)

Although standards for Gauge 1 have existed for years, many large scale products have back to back wheel dimensions that are significantly less than the standard.


Does anyone know the smallest back to back measurements for commercial products that exist in the market?

Thanks

Stan


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## Greg Elmassian (Jan 3, 2008)

Are you asking for the worst example, or the average of the worst manufacturer? 

It's probably not fair to find one out there, but a consistent poor average. 

It used to be Aristo, but no longer, they have radically improved this spec, especially on their new contour wheels. 

I don't have any LGB right now, but it would be worth checking, they are consistent and the combination of deep and thick flanges means either the gage or the back to back is out. 

USAT is always narrow on their locos, but easily adjusted. 

Greg


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## East Broad Top (Dec 29, 2007)

The narrowest I measured when working with the standards a few years ago was, if I recall, right around 1.535" on an LGB loco, and I think one Aristo example was in that ballpark, too. Measurements that narrow tended to be the exception. A "typical" narrowest measurement was on the order of 1.550" or so. 

Later, 

K


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## StanleyAmes (Jan 3, 2008)

Thanks

That was the information I needed.

Stan


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## Pete Thornton (Jan 2, 2008)

Does anyone know the smallest back to back measurements 
Stan, 
The original Bachmann 2-4-2T "Lyn" (and presumably the US black version) had really think flanges. When I ran it on Clem's track, it lifted a wheel over the check rails, so it was seriously compromised in back-to-back. My loco is upstairs - I'll take the measuring gear up and report back.

Edit: not as bad as I recalled - this one is about 1.550". Kevin wins!
P.S. My LGB 'cow-paint' 0-4-0 is exactly 1.575" - and the flanges are finer than my Bachmann 'Lyn'.


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## jfrank (Jan 2, 2008)

Posted By StanleyAmes on 12 Sep 2012 08:55 PM 
Although standards for Gauge 1 have existed for years, many large scale products have back to back wheel dimensions that are significantly less than the standard.


Does anyone know the smallest back to back measurements for commercial products that exist in the market?

Thanks

Stan


I have found that most all Bachman stuff is narrow gauged. I use the Old Pullman gauge to check everything. It has all the standard measurements built in. Item #19760. http://www.oldpullmanmodelrailroads...Gauges.pdf


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## Greg Elmassian (Jan 3, 2008)

I've seen that gauge I believe. Does not do min and max if I remember correctly. 

Believe it or not, the stainless steel Aristo gauge is great. 

Greg


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## Paul Burch (Jan 2, 2008)

Why is everyone so concerned with back to back, like if the back to back is ok then the world is right? It is only part of the equation. Gauge is just as important. If back to back is narrow and you correct that but the flanges are too thick and it makes the gauge too wide then you have another problem, the loco or car will not set or ride on the rail like it should. Just look at the problem Aristo has with the new 2-8-0. They corrected the back to back and caused a gauge problem. They have since announced a new wheel design but as yet it has not materialized.


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## Amber (Jul 29, 2011)

Back to back measurement is mostly for proper operation through the switch frogs and guard rails. If it's too narrow, the wheels will ride up over the frog and derail.


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## Paul Burch (Jan 2, 2008)

Amber,
That is why back to back and gauge are equally important.


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## Nutz-n-Bolts (Aug 12, 2010)

That is why back to back and gauge are equally important.

You are right, but but the missing factor in what you are saying is flange thickness. Back to back and rail gauge dictate the thickness of the flange. If a manufacturer gets the flange wrong it will make one or both of the other two wrong.

Sounds like Stan want's to try and make sure his flange rails are adjusted to clear the worst. Am I close?


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## Amber (Jul 29, 2011)

The expensive alternative is to buy aftermarket wheels with the proper flanges so that the wheels can be gauged correctly.


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## Paul Burch (Jan 2, 2008)

Or have a machinist turn them like I did.


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## Greg Elmassian (Jan 3, 2008)

You need all three clearly. 

But most derailments occur in switches, and unless you have grossly thick flanges (which really put you out of the game) the more "critical" dimension to good running is back to back, since that's what really controls the wheels through switches. 

That's often the reason for the focus. 

By the way, Aristo has reduced the flange thickness on the latest design of their diesel wheels, in that it's just about perfect in my opinion and meets both NMRA and G1MRA specs. I've entreated Scott Polk personally to reflect this contour in stainless wheels for the diesels and on the steam locos. 

My page is not complete yet, but the measurements of the new Aristo wheels is on my web site: *http://www.elmassian.com...trong>**

I have to say: Good Job Aristo!

Greg*


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## jfrank (Jan 2, 2008)

Posted By Greg Elmassian on 13 Sep 2012 10:31 AM 
I've seen that gauge I believe. Does not do min and max if I remember correctly. 

Believe it or not, the stainless steel Aristo gauge is great. 

Greg 

It measures flange to flange, which is more important than back to back. It also has switch demensions such as guard rail and flange width measurements. It's a very useful tool. I don't know why you people always degrade it with your comments. Anyway, it works very well for me and I don't have derailments due to wheel gauge or track standards. And, I don't have to run around with a micrometer in my hand checking everything nor do I have to remember or look up what the 'standards' are.


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## Greg Elmassian (Jan 3, 2008)

I disagree John on "flange to flange" because I believe it measures the TIP / outer edge of the flange. 

That is not the "working surface". I can't get a picture of it, but if it is as gross as the one on the Kadee gauge, it's pretty worthless for precise measurements. 

Please provide a picture of your gauge so we can look at this objectively. 

We're all fine that you like it and works for you and you don't have derailments. 

You're pretty testy over this, sort of casting aspersions about "running around with a micrometer in my hand".... I think that level of angst does not need to be thrown at "you people".... 

Why don't we keep this on a non personal, objective level? 

Kevin, Stan and I have done extensive work in this area, and we're well aware of how stuff works. 

Looking forward to your picture of your gauge. 

Greg


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## jfrank (Jan 2, 2008)

Posted By Greg Elmassian on 14 Sep 2012 09:37 AM 
I disagree John on "flange to flange" because I believe it measures the TIP / outer edge of the flange. 

That is not the "working surface". I can't get a picture of it, but if it is as gross as the one on the Kadee gauge, it's pretty worthless for precise measurements. 

Please provide a picture of your gauge so we can look at this objectively. 

We're all fine that you like it and works for you and you don't have derailments. 

You're pretty testy over this, sort of casting aspersions about "running around with a micrometer in my hand".... I think that level of angst does not need to be thrown at "you people".... 

Why don't we keep this on a non personal, objective level? 

Kevin, Stan and I have done extensive work in this area, and we're well aware of how stuff works. 

Looking forward to your picture of your gauge. 

Greg 
Well Greg, I have been in this hobby for 50 years so I am also 'well aware' of how things 'work'. If you want a picture, you will just have to spend $10 and get one for yourself. People ask simple questions on here and get 'rivette counter' answers. I gave you the link. I offered it as a simple solution to this same question that gets asked over and over on here. My suggestion is to just do what works for you. You can make it simple or complex. Your choice.


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## Greg Elmassian (Jan 3, 2008)

Funny the web site has no picture. Could not find one. 

I like simple, and the Aristo gauge makes it very simple with go and no go. 

It's quite a value for the money.


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## jfrank (Jan 2, 2008)

The Old Pullman is similar to the NMRA Type II style gauge and gives the same measurements. Here is a link and pic. http://www.nmra.org/standards/sandrp/rp2.html 

I know there are people on here that like to make fun of the NMRA standards and call them names like enema ray, etc. But dudes, that is why you have no standards in this gauge. That is why each manufacturers stuff only runs best on their track. Every other scale from Z to O adheres to NMRA standards and the manufacturers even state such on the box. I use Llagas Creek track and switches which adhere to these standards as do my Accucraft engines and rolling stock. Bachman stuff, I have to adjust the wheel gauge always. Aristo track switches are hopelessly out of gauge and border on junk. I have even found Aster engines with things like pilot wheels out of gauge. If you don't check this stuff and correct it then you will always have problems. On our club track we used some Aristo #6 switches that were donated. Everyone had the guard rails out of guage and had to be fixed. Every manufacturer has their own style of couplers. Most won't mate with any other and are at different heights. No other gauge has this problem. Gauge One in the US is a mess.


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## Greg Elmassian (Jan 3, 2008)

Ahh... well if it's a Type 1 gauge, it's a "forgiving" as a Kadee gauge. If it's a type II gauge, it would be worth buying. 

When you say "no standards" you mean that the manufacturers do not adhere to any standard, right? 

You DO know that the NMRA and for even longer and with less "messing about" the G1MRA have standards right? 

I agree that stuff is normally all over the map. I will reiterate though, that if you buy a new Aristo Dash 9, you will have something that meets both standards. I hope this is the beginning. Aristo is a large component of what is available in "G". Maybe Stan can help pull Bachman along. I'm not as hopeful for USAT, but luckily their locos are all adjustable. 

Greg 

p.s. Kadee will overcome in most G scale stuff, like it did in the smaller scales.


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