Trains.com

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Width of an NMRA Standards Gage

5277 views
50 replies
1 rating 2 rating 3 rating 4 rating 5 rating
  • Member since
    May 2004
  • 7,362 posts
Posted by 7j43k on Saturday, August 7, 2021 4:03 PM

SeeYou190

 

 

It looks like what I thought was correct. The total width of the gage is not used for checking anything.

Am I missing something?

 

 

 

You use the "total width of the gage" to check for NMRA horizontal clearance on straight track.

Considering that the width of the MARK V gage mirrors almost exactly the required clearances in Washington and Oregon (and likely elsewhere), it's not totally useless. It's also good for having a place to put all the notches and bumps.

That funny little notch on the left is to check platforms.

Oh.  It turns out the MARK II Standards Gage was issued in the early sixties, to reflect the new RP25 flanges.  I doubt the MARK I was marked with a "I".  I MIGHT have one somewhere.  I MIGHT have lotsa things.  Somewhere.

Pretty sure I've got a MARK II.

Ed

  • Member since
    January 2017
  • From: Southern Florida Gulf Coast
  • 15,285 posts
Posted by SeeYou190 on Saturday, August 7, 2021 3:35 PM

7j43k
Here's the official directions:

Thanks Ed.

It looks like what I thought was correct. The total width of the gage is not used for checking anything.

Am I missing something?

-Kevin

Living the dream and happily modeling my STRATTON AND GILLETTE Railroad in HO scale. The SGRR is a freelanced Class A railroad as it would have appeared on Tuesday, August 3rd, 1954, in my personal fantasy world of plausible nonsense.

  • Member since
    May 2004
  • 7,362 posts
Posted by 7j43k on Saturday, August 7, 2021 3:33 PM

selector

I don't know, but my guess is that as longer rolling stock became more widely used, and modelers developed a robust market for large steamers, it became necessary for 'recommended' clearances to reflect a wider safety margin irrespective of actual prototype dimensions and practices.

 

Longer rolling stock isn't involved here, as we're talking about a gage that's designed for straight track.  It's the width, only.

Yup, there's a robust market for large steamers.  But I doubt that their overall width is significantly greater than "medium" ones.  That's a tougher one to nail down though.  I just paged through a diagram book for SP&S steam, and the railroad didn't list extreme widths.  They must have thought it unimportant.

 

Ed

  • Member since
    May 2004
  • 7,362 posts
Posted by 7j43k on Saturday, August 7, 2021 3:24 PM

Here's the official directions:

https://www.nmra.org/sites/default/files/standards/sandrp/pdf/rp-2_2019.07.07_typo_correctiontrack_gages.pdf

 

I see there are some videos on the subject, too.

 

Ed

  • Member since
    January 2010
  • 2,614 posts
Posted by peahrens on Saturday, August 7, 2021 3:21 PM

ATLANTIC CENTRAL
My old one is smaller, one I just bought from the NMRA last year is bigger. Sheldon

That's what Hersheys and others do with candy bars.  A Snickers was 5 cents.  They made it bigger and charged 10 cents.  Then they made the 10 cent bar smaller again, etc.  Expect the next NMRA gage version to be smaller but cost the same, then a larger, more expensive version a few years after that, and so on.

Or, it's like fashion for (wearable) ties: wide ties are in, skinny ties are then in, then wide ties again, etc.Big Smile

Paul

Modeling HO with a transition era UP bent

  • Member since
    January 2017
  • From: Southern Florida Gulf Coast
  • 15,285 posts
Posted by SeeYou190 on Saturday, August 7, 2021 3:10 PM

Mine is a Mark IV.

Does anyone have a link to the instructions for how to use it? I think that would be very helpful. I have a feeling some contributors are are not using the gage the same as others, or maybe we are talking about something the gage is not even intended to be used for.

I do not use my gage to check clearances. I use an 86 foot high cube boxcar for that. I space my tracks wider than NMRA recommendations for finger clearance.

-Kevin

Living the dream and happily modeling my STRATTON AND GILLETTE Railroad in HO scale. The SGRR is a freelanced Class A railroad as it would have appeared on Tuesday, August 3rd, 1954, in my personal fantasy world of plausible nonsense.

  • Member since
    February 2005
  • From: Vancouver Island, BC
  • 23,101 posts
Posted by selector on Saturday, August 7, 2021 2:50 PM

I don't know, but my guess is that as longer rolling stock became more widely used, and modelers developed a robust market for large steamers, it became necessary for 'recommended' clearances to reflect a wider safety margin irrespective of actual prototype dimensions and practices.  A responsive governing body will listen to feedback and complaints about a protocol's or a device's deficiencies, and they'll make adjustments so that those things offer more utility to their constituency and membership.

  • Member since
    May 2004
  • 7,362 posts
Posted by 7j43k on Saturday, August 7, 2021 2:31 PM

Mark,

 

Equipment has NOT gotten wider over the years.

In 1955, Plate B (the only one shown in my ORER) width was 10'-8".

In 2015, all Plates showed a maximum width of 10'-8".

 

I expect the widening of the gage was done for good and thoughtful reasons.  But it wasn't done because the prototype got wider.

 

Ed

  • Member since
    February 2001
  • From: Wyoming, where men are men, and sheep are nervous!
  • 3,113 posts
Posted by Pruitt on Saturday, August 7, 2021 2:09 PM

As equipment widths on the prototype has changed over the years, the NMRA has changed their standards gage as well. Some of the changes were done to reflect prototype changes, and some were done to reflect NMRA Standards changes. Equipment has gotten somewhat wider over the years. So has the gage.

So it isn't surprising that different variants of the gage have different dimensions (otherwise, why would there be different variants in the first place?).

  • Member since
    February 2010
  • From: Indiana
  • 212 posts
Posted by mikeGTW on Saturday, August 7, 2021 1:05 PM

7j43k
You're sitting on a FORTUNE, man.  DON'T loose that! No.  Wait.   Can I have it for my collection?   Ed

 

I wish   $10 on evilbay

  • Member since
    January 2009
  • From: Maryland
  • 11,602 posts
Posted by ATLANTIC CENTRAL on Saturday, August 7, 2021 12:41 PM

7j43k

Yup.  "Gage".  That's how it's spelled on my NMRA standards gage.

Anyway.

In the topic "Yard Track Spacing and Radius...", there has been some discussion on how wide the Standards Gage is.

Mike said first that his was 2 3/16" wide.

I said that I felt differently--that it was 2 1/16" wide.  I just measured mine again (a MARK IVb) with a micrometer, and it is 2.063 wide.  That's 2 1/16".

 

That's an eighth of an inch difference!  For a GAGE!

 

Very curious, I thinks.  I just checked the NMRA Recommended Practice for this dimension, and got 2 X 1.10", or 2.20".  THIS is very close to the 2 3/16" reported by Mike and others.

And yet, I'm holding an official NMRA gage that says different.

At least online, it doesn't appear that NMRA keeps historical information about any dimension changes over time.

However, it so happens I have copies from Olden Times.  The dimension under discussion was shown as 2 X 1", or 2", in a 1959 copy of Standard S-8.

 

So, over time, we have a Standard Dimension changing, without notation in the Standards.  And/or the Recommended Practices.

 

To date, I've never used my various NMRA Standards Gages to check this dimension.

I'll note here that the current 2.2" matches the structure clearances noted in both Washington and Oregon railroad clearance standards from the fifties.

 

I post this topic to explain the differences reported in the other topic, and to reveal a certain fluidity in NMRA standards, generally undiscussed.  I should dig out my OLD NMRA gage, buy a new one, and build a display of "NMRA Gages over the years".

 

Ed

 

 

 

My old one is smaller, one I just bought from the NMRA last year is bigger.

Sheldon

    

  • Member since
    January 2009
  • From: Bakersfield, CA 93308
  • 6,524 posts
Posted by RR_Mel on Saturday, August 7, 2021 12:25 PM

When I was building one of my camera cars I made a CAD drawing to scale of my NMRA Gage using my digital caliper.



It was very helpful with the design of the car.



I was able to keep the camera movement within the needed clearance of my tunnel portals.



Mel
 
Modeling the early to mid 1950s SP in HO scale since 1951



My Model Railroad    
http://melvineperry.blogspot.com/
 
Bakersfield, California
 
Aging is not for wimps.

  • Member since
    May 2004
  • 7,362 posts
Posted by 7j43k on Saturday, August 7, 2021 12:24 PM

mikeGTW

Ed

I guess I'm kind of behind the times  mine is a Mark II gage  and it is 2" wide

 

 

You're sitting on a FORTUNE, man.  DON'T loose that!

No.  Wait.  

Can I have it for my collection?

 

Ed

  • Member since
    February 2010
  • From: Indiana
  • 212 posts
Posted by mikeGTW on Saturday, August 7, 2021 11:54 AM

Ed

I guess I'm kind of behind the times  mine is a Mark II gage  and it is 2" wide

  • Member since
    May 2004
  • 7,362 posts
Width of an NMRA Standards Gage
Posted by 7j43k on Saturday, August 7, 2021 11:44 AM

Yup.  "Gage".  That's how it's spelled on my NMRA standards gage.

Anyway.

In the topic "Yard Track Spacing and Radius...", there has been some discussion on how wide the Standards Gage is.

Mike said first that his was 2 3/16" wide.

I said that I felt differently--that it was 2 1/16" wide.  I just measured mine again (a MARK IVb) with a micrometer, and it is 2.063 wide.  That's 2 1/16".

 

That's an eighth of an inch difference!  For a GAGE!

 

Very curious, I thinks.  I just checked the NMRA Recommended Practice for this dimension, and got 2 X 1.10", or 2.20".  THIS is very close to the 2 3/16" reported by Mike and others.

And yet, I'm holding an official NMRA gage that says different.

At least online, it doesn't appear that NMRA keeps historical information about any dimension changes over time.

However, it so happens I have copies from Olden Times.  The dimension under discussion was shown as 2 X 1", or 2", in a 1959 copy of Standard S-8.

 

So, over time, we have a Standard Dimension changing, without notation in the Standards.  And/or the Recommended Practices.

 

To date, I've never used my various NMRA Standards Gages to check this dimension.

I'll note here that the current 2.2" matches the structure clearances noted in both Washington and Oregon railroad clearance standards from the fifties.

 

I post this topic to explain the differences reported in the other topic, and to reveal a certain fluidity in NMRA standards, generally undiscussed.  I should dig out my OLD NMRA gage, buy a new one, and build a display of "NMRA Gages over the years".

 

Ed

 

 

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Search the Community

ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT
Model Railroader Newsletter See all
Sign up for our FREE e-newsletter and get model railroad news in your inbox!