# Wheel Guage?



## John J (Dec 29, 2007)

Ok I know this has been asked a billion times but it is 1 am and I am too lazy to look for it. 

What is the spaceing of metal wheels back to back? 

I thought it was 1.56 or something like that I think 1.75 is too much.

We are talking inches here not MM.


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## JEFF RUNGE (Jan 2, 2008)

John, G1MRA lists 1.574 or 1.654 depending on wheel profile and size.


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## Jerry Barnes (Jan 2, 2008)

1.75 is the distance between the rails JJ, set them like that and they will fall off.


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## East Broad Top (Dec 29, 2007)

Go with 1.575, unless you have really thick flanges (>.075" each flange), in which case you can cut back to 1.560 to compensate for the increased flange thickness. Aristo-Craft uses a narrower back-to-back spacing as standard on their locomotives (around 1.535"). I wouldn't go that far for wheels, because you then run the risk of having the wheels too close together to where they may fall between the rails (if the tread is narrow enough). 

The 1.654" back-to-back spacing Jeff mentions is taken from G1MRA's "finescale" standards. If anyone is able to run G1MRA's finescale standards on the typical garden railroad (i.e, anything other than a solid concrete slab as a foundation) then I'm nominating them for sainthood because they are truly blessed. 

Later, 

K


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## Bruce Chandler (Jan 2, 2008)

I don't think I'd call Aristo spacing "standard" at all. On my Pacific, the BTB was anywhere from 1.522 to 1.535. 

Now they're all 1.574, but I had to do a LOT of grinding.


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## Greg Elmassian (Jan 3, 2008)

Funny that none of the Aristo wheels ever meet the standards on the Aristo gauge.

I've studied this a bit, and here is my web page referring to a number of the standards:
*http://www.elmassian.com/trains-mai...ainmenu-95* 


The relevant back to back is normally expressed as minimum and maximum. Recently several standards have issued a "target value":



*Wheel back to back maximum (Aristo out of spec (too wide) for existing NMRA standards, just meets G1MRA max)
*
[*]1.755" Kadee gauge (Note: there are 2 notches, this is the measurement of the notches, when used to set an old Aristo "split axle" wheelset, it set the back to back at *1.587*", EXTREMELY dependent on flange contour)[*]*1.594" Aristo gauge actual (Ted Doskaris measured 1.595")*[*]1.594" G1MRA Standard (Note target is 1.574")[*]1.586" S-4.3 Proposed standard (Hi-Rail) (Note target is 1.582")[*]1.582" S-4.2 Proposed standard (Standard) (Note target is 1.580")[/list]


*Wheel back to back minimum (Aristo too wide/restrictive in all cases, the true allowable minimums are smaller)*
[*]1.591" Kadee gauge (Note: there are 2 notches, this is the measurement of the notches, when used to set an old Aristo "split axle" wheelset, it set the back to back at 1.587", EXTREMELY dependent on flange contour)[*]*1.575" Aristo gauge actual*[*]1.574" G1MRA Standard (Note target is 1.574")[*]1.567" S-4.3 Proposed standard (Hi-Rail) (Note target is 1.582")[*]1.567" S-4.2 Approved standard (Standard) (Note target is 1.580")[/list]

After all that, my personal pick is 1.574" the G1MRA target measurement.

Regards, Greg


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## Bruce Chandler (Jan 2, 2008)

Yes, I'm guessing you're not supposed to use the Aristo gauge with Aristo locomotives?









Man, aren't those some THICK flanges?


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## East Broad Top (Dec 29, 2007)

Just to clarify (or muddy the waters further, depending on your take), the NMRA standards Greg references will (with any luck) be changing in the near future to something more consistent with large scale practice. These new standards are currently going through the preliminary acceptance process, and should--with any luck--be put forth for public comment in short order. Note: these standards are different from what is currently on the NMRA's web page as being considered as of July 2009. 

These new standards come largely from outside the NMRA. They wanted our guidance and input on this. Those of you who have the latest _Scale Rails_ know where this is coming from. 

Later, 

K


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## aceinspp (Jan 2, 2008)

Ya you can use the AC gage on there locos and it sure will tell you they screwed up. Pretty bad when there own products do not comply with there gage. Later RJD


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## Greg Elmassian (Jan 3, 2008)

That's why I included the G1MRA, and on my web page the MOROP/NEM standards, I considered everything I could find..... 

Heaven knows where the NMRA is going.... 

Greg


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## Greg Elmassian (Jan 3, 2008)

Thanks for reminding me Kevin, the standards changed in July, and I forgot to copy down what they changed to...

An improvement in my opinion, but with a tolerance of +/- .002", I cannot believe that any manufacturer will abide by these tolerances...


Here's the current info... 




*Wheel back to back maximum (Aristo out of spec (too wide) for existing NMRA standards, just meets G1MRA max)
*
[*]1.755" Kadee gauge (Note: there are 2 notches, this is the measurement of the notches, when used to set an old Aristo "split axle" wheelset, it set the back to back at *1.587*", EXTREMELY dependent on flange contour)[*]*1.594" Aristo gauge actual (Ted Doskaris measured 1.595")*[*]1.594" G1MRA Standard (Note target is 1.574")[*]1.582" S-4.2 standard (standard 1:20.3 ) (Note target is 1.580")[*]*1.576 NMRA target*[*]1.574" S-4.3 standard (Hi-Rail) (Note target is 1.576")[*]1.574" S-4.2 standard (Standard LS) (Note target is 1.576")[/list]


*Wheel back to back minimum (Aristo too wide/restrictive in all cases, the true allowable minimums are smaller)*
[*]1.591" Kadee gauge (Note: there are 2 notches, this is the measurement of the notches, when used to set an old Aristo "split axle" wheelset, it set the back to back at 1.587", EXTREMELY dependent on flange contour)[*]1.578" S-4.3 standard (Hi-Rail) (Note target is 1.576")[*]1.578" S-4.2 standard (Standard LS) (Note target is 1.576")[*]*1.576 NMRA target*[*]*1.575" Aristo gauge actual*[*]1.574" G1MRA Standard (Note target is 1.574")[*]1.567" S-4.2 standard (Standard 1:20.3) (Note target is 1.580")[/list]


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## East Broad Top (Dec 29, 2007)

Greg, those are also not the correct numbers, so don't bother copying them down. The new Large Scale standards proposal will be posted on the web site, but I don't know when exactly. (It's on the working group's "to-do" list.) Don't worry. The NMRA is headed the right direction on this. As I said above, it's being led by the large scale community, and the NMRA has been very receptive. They want something workable and easy to follow as much as we want clarity and cohesiveness between the various hobby organizations. 

Later, 

K


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## Greg Elmassian (Jan 3, 2008)

Kevin, those are the correct numbers right now... and when they are changed and official, I'll change them again... they are what is on the NMRA web site right now. 

(seems really stupid to change them in July and then right afterwards...)

I look upon what the NMRA does more with amusement than it being well thought out, but maybe it will get better, I have an open mind.


What I have done is read and study and learn, and then take other's experience and successes and failures into account. I've talked to manufacturers of trains and track. Then I tried to make some sense of it, and talked to people that know track backwards and forwards on real railroads to understand why they do things the way they do. 



Then apply what I have learned and figured out on my owne to my layout. Since I can run 45 car trains on tight curves with a 3.4% grade reliabliy, I think I'm probably ok with what I have chosen, wouldn't you agree?

Regards, Greg


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## East Broad Top (Dec 29, 2007)

Kevin, those are the correct numbers right now... and when they are changed and official, I'll change them again... they are what is on the NMRA web site right now. 
They are the numbers on the web site, but they are _not_ correct--hence my post advising readers here to disregard them. Until the site is changed, letting people know through forums like this is the only way to get the word out. The numbers will be changed on the site in due course to reflect the current proposal. The working group has to get the numbers to the web guru, who has to update the site... etc. and so forth. There is a level of bureaucracy that has to be contended with that takes a bit of time. 

(seems really stupid to change them in July and then right afterwards...) 
What was put forth in July was the wrong set of numbers, inserted into the overall proposal for all scales so that it could be voted upon at the national convention. None of the members on the working group really know where those numbers specifically came from, hence the quick action to take corrective measures. The Large Scale standards as currently posted (under the July proposal) have essentially been vacated pending the proposal from the working group. That proposal is currently working its way through the review process. 'Tis the wiser course of action to correct a mistake forthright than to let it fester. 

I look upon what the NMRA does more with amusement than it being well thought out, but maybe it will get better, I have an open mind. 
There's a lot of that going around--certainly history seems to favor that impression. That's precisely why this proposal has been developed outside the direct influence of the NMRA. This isn't "them" telling "us" what to do. This is very much both communities sitting down and working together under a rather diplomatic understanding. (Dare I say "bipartisan?") There's a good team working on this, and there's been a productive--and downright frank--dialog established along the way. When the NMRA gives three pages of its publication to a rather outspoken critic of that group to lay things on the line, It's hard to say they're not open to hearing new ideas. Response to that critique has been very positive from large-scale modelers within the NMRA. 

What I have done is read and study and learn, and then take other's experience and successes and failures into account. I've talked to manufacturers of trains and track. Then I tried to make some sense of it, and talked to people that know track backwards and forwards on real railroads to understand why they do things the way they do. 

Then apply what I have learned and figured out on my owne to my layout. Since I can run 45 car trains on tight curves with a 3.4% grade reliabliy, I think I'm probably ok with what I have chosen, wouldn't you agree? 
A very pragmatic approach--not at all unlike the approach taken by the working group. I think you will find that similar methods yield similar results. 

Later, 

K


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## Greg Elmassian (Jan 3, 2008)

Kevin, take this the right way, since you seem to be involved: 

Putting incorrect information as an approved standard on the NMRA site is just damn sloppy, and inexcuseable. You mean someone could not at least put a single line of text stating that what you are reading is wrong? 

That is unbelievable.. It has to be 30 seconds worth of work on a web site. 

On the further parts of your response, the NMRA voted on and approved screwed up numbers? Now just hold on a second. The standards that were on the site were marked "proposed" for the last year, and were to be approved in July. 

Now, in July, the standards show as approved and are DIFFERENT!!! My faith in the NMRA is about zero now... this is nuts. At the last second, what has been published as proposed was "switcherooed" with something else !!!! 

So, I'm further convinced that the NMRA is becoming not only worthless in it's ability to evaluate and recommend on G scale, but, that they are UNTRUSTWORTHY, this appears on the surface to be DEVIOUS. 

Before you put up some big response, remember: 

There was a "proposed" standard up for about a year, and then in July when it was to be accepted, IT WAS CHANGED. 

read that over again and again.... this kind of action has proven to me that whoever is in charge, be it a person or group, is not what I consider TRUSTWORTHY. 

What a terrible thing. I threw away my NMRA renewal notice. After my other experience in a working group, it will take YEARS for me to believe anything from the NMRA without a lot of proof and investigation and time. 

I will stop recommending trying to follow the NMRA RP's and standards until the NMRA proves to me that it is again worthy of my TRUST... it is a terrible day, I had hopes... 

Regards, Greg


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## East Broad Top (Dec 29, 2007)

...Putting incorrect information as an approved standard on the NMRA site is just damn sloppy, and inexcuseable. You mean someone could not at least put a single line of text stating that what you are reading is wrong? 

That is unbelievable.. It has to be 30 seconds worth of work on a web site. ... 
Hey, I agree--the numbers should have been pulled from the proposal as soon as the working group was formed to re-examine them. I suspect that's likely the genesis of the miscommunication. The working group was always operating under the premise that what was in the original proposal was to be tabled in lieu of what we were working on. 

...On the further parts of your response, the NMRA voted on and approved screwed up numbers? Now just hold on a second. The standards that were on the site were marked "proposed" for the last year, and were to be approved in July. 
Yes, the NMRA voted on "screwed up" numbers--numbers that should have been tabled from when the WG was formed. That was our understanding. 

Now, in July, the standards show as approved and are DIFFERENT!!! My faith in the NMRA is about zero now... this is nuts. At the last second, what has been published as proposed was "switcherooed" with something else !!!! 

So, I'm further convinced that the NMRA is becoming not only worthless in it's ability to evaluate and recommend on G scale, but, that they are UNTRUSTWORTHY, this appears on the surface to be DEVIOUS. 

Before you put up some big response, remember: 

There was a "proposed" standard up for about a year, and then in July when it was to be accepted, IT WAS CHANGED. 

read that over again and again.... this kind of action has proven to me that whoever is in charge, be it a person or group, is not what I consider TRUSTWORTHY. 

Okay... Let me clarify... The standards that have been up for the past year (or more) are the wrong-sighted standards which originally caught my attention. I know you've read one of my early position papers relative to those posted standards, why they would not be accepted by the large scale community, and what I thought needed to be done to correct that. It was that paper which garnered me the invitation to join this effort, working with a handful of other large scale hobbyists within and outside the NMRA. We did so under the understanding that the numbers on the proposal were essentially null and void, and that the BOD would not consider them as part of the overall standards revision pending receipt of our proposal. 

We submitted our draft proposal on June 3rd. Unfortunately, the proposal didn't have sufficient time to go through the proper vetting and review channels prior to the BOD meeting in July, so the full proposed standards were never amended to include our new numbers. When the board met in July to approve the standards package for all scales, they had left the old standards in place. For whatever reason, they had never been officially tabled from the proposal. Rather than tabling the entire package, the board went ahead and approved things with the understanding that the working group had revised large scale standards which they would revisit at the next meeting. 

Read into that what you will about the efficiencies and inefficiencies of the process. My words aren't going to change anyone's opinion on the NMRA. Only their actions can do that. My concern is with setting the facts straight, making sure no one's using bad information when considering standards, and ultimately passing standards which mesh with the desires of the large scale community. 

Later, 

K


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## Curmudgeon (Jan 11, 2008)

See what happens when you get away from the Kool-Aid trough?
Proud of you, Kevin.

And, if you think they'll actually get it right and not screw up all the existing stuff, well, I remember 5 standards for 5 scales.

This shall be good for the aftermarket wheel manufacturers. though.
We can all buy sets for the standard that worked and change them all out!

Good thing I quit buying anything in #1 gauge with wheels on it.

Back to log-off configuration.....found that the "active topics" works well when you are not logged in.


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## Les (Feb 11, 2008)

Posted By Jerry Barnes on 20 Sep 2009 08:38 AM 
1.75 is the distance between the rails JJ, set them like that and they will fall off. 


Just when I'm at last getting ready to build some track, and you come up with that! Thank you, thank you, thank you!









Les


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## Greg Elmassian (Jan 3, 2008)

Thanks Kevin, keep plugging away at it. 

I'm glad this was not a fight over what is really published on the site. 

Is there a way I can see the "real" stuff? Even if I cannot reveal it? 

I truly am in search of something better than G1MRA (I think they could improve some things) and definitely the MOROP stuff is wide open. 

Regards, Greg


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## aceinspp (Jan 2, 2008)

From my take the NMRA can set a standard for the G scale but don't bet on the manufactures to comply with it. Till you get the manufactures to agree all is for not. Later RJD


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## East Broad Top (Dec 29, 2007)

RJD, that's the million dollar issue. Time will tell. You know what they say about leading horses to water... The good news is that I think the manufacturers seem to _want_ workable standards now, where before the market was led by a very dominant player who eschewed standards of any kind. (to the point of having different wheel profiles on the same locomotive!) 

Later, 

K


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## Bruce Chandler (Jan 2, 2008)

And now we have a manufacturer that has three different BTB distances on a loco with three driver axles. And none of those BTB are close to their own BTB recommendations on their own gauge. 

I'd love to have a good standard, but I'm sure not holding my breath.


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