# Standard Gauge Spacing.



## John J (Dec 29, 2007)

Standard gauge spacing of the rails is 56.5 ?

Is there a + or - tolerance permitted ?

JJ


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## Greg Elmassian (Jan 3, 2008)

* http://en.wikipedia.org/wiki/Track_gauge*

*http://www.fra.dot.gov/Pages/1232.shtml *

Of course, for our models, you should use a standard that takes into account our non-prototype dimensions for flanges, wheel contours, etc.


Need to cut and paste the following in your browser, fighting the editor 


http://www.gaugeone.org/Misc/STANDARD DIMENSIONS FOR GAUGE ‘1’.pdf

http://www.nmra.org/standards/sandrp/pdf/S-3.3 2010.02.24.pdf 





Greg


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## aceinspp (Jan 2, 2008)

Tho the sites mentioned above reflect some specs I do wish they would use the correct wording for Gage and this is correct spelling as used in the FRA books. As mentioned, There are minimum standards set for gage based on speed which then puts it into a class. The max allowable gage is 4 ft 10 and 1/4 inches which is for excepted track. the lest amount of gage is 4 ft 8 inches for any track class 1 and above. 

I do not think we would want to really play much with the gage of track in our scale as the locos and cars are all over the place for back to back spacing. So now we have majors issues. However one manufacture of track tended to have gage so close to the specs that a certain new loco would not traverse the rail without derailing. Later RJD


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## Greg Elmassian (Jan 3, 2008)

So, as usual, JJ, you asked a question, but we KNOW you have something interesting in mind!! Can you let us in on it since we helped out? 

Greg


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## Bill Swindell (Jan 2, 2008)

The + or - depends on the class of track.

Class 5 is rated at over 100 MPH
Class 4 is rated at 79 MPH

all the way down to Class 1 which is pretty sick stuff. I have a lot of experience running on Class 1 track.


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## bnsfconductor (Jan 3, 2008)

Is class 1 the same as excepted track? I've ran on some excepted track, it was really bad, but then again the RR wanted to abandon the branch line so I guess it was reason for not working on the track. 

Craig


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## aceinspp (Jan 2, 2008)

Sorry Bill your a bit over on speeds on your class of tracks. Hope you do not loose your engineers license if your operating a loco. Max speed for class 5 is 90 for pass and 80 for freight. Later RJD


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## Torby (Jan 2, 2008)

And why 4 ft 8 1/2 inches?

I like the horse's backside story.

When Stephenson started building his first Standard Gauge line, the engineers (not the train drivers, the designers) had figured out that you don't need a wheel flange on both the inside and outside of the rail, but hadn't yet figured out that the flange is best on the inside. When they did figure that out, Stephenson had most of his track laid. So instead of moving a rail, he just mounted the wheels on his rolling stock with the flange inward and specified the inside dimension of his existing track which was -- tada -- 4 ft 8 1/2. 


If you take a tape measure out to your neighborhood railroad, watch for trains. You'll find the track is 5 ft 2 inches from outside to outside. Was this Stephenson's original idea? Nope! A modern rail is an inch wider than Stephenson's rails. His original plan was for 5ft track outside to outside. 


References? Sorry, this ADD brat read it somewhere. He even took a tape measure out to an old piece of track and measured.

Also, ties are meant to keep the gauge, not support the train. They're not strong enough to carry the weight of the train. When they build track, they're careful to support the ties under the rails with ballast, *not* under the middle of the tie. If the tie is supported in the middle, it'd break as the train rolls over. In USA, standard ties are 6 by 8 inches, +- 1 inch either way, and 8 ft long. Switch ties are longer.


So, why the heck do our switches contain a "Frog?" That part of a standard gauge switch consists of 2 pieces of rail bent around a casting. One end of each rail connects to the rails to the points, and the other end becomes the guard rail on the inside of the flange. When the thing is laying on the ground, by golly, it looks a bit like a frog! It's also VERY heavy.


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## work4fil (Jan 4, 2008)

Wait a minute, wasn't the "gauge" the same width as the roman chariots? 

I had read that somewhere in one of those "Useless Information Guides" passed out at work. 

I am interested what is in JJ's mind. 

Fil


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## Scottychaos (Jan 2, 2008)

Track gauge and roman chariots


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## Semper Vaporo (Jan 2, 2008)

Posted By work4fil on 06 Nov 2011 08:58 PM 
Wait a minute, wasn't the "gauge" the same width as the roman chariots? 

I had read that somewhere in one of those "Useless Information Guides" passed out at work. 

I am interested what is in JJ's mind. 

Fil 

The story of the Roman horse's backside width being the cause of modern RR's using the odd 4-ft, 8.5-in. gauge is almost as old as RRs themselves. I have it in a book that was written in the 1890's and it says it is "an OLD story of little credance". Of course the story in that book does not include the stuff about the diameter of the Space Shuttle booster engines being determined by the width of the RR tunnel they had to pass through.

Actually, some time ago there was quite a discussion on the internet on the early RR "List" forums and someone from England went and measured some of the ruts that still exist in old Roman roads there and reported that they were NOT 4-ft 8.5-in, but I don't remember what gauge was reported. Then someone from Italy did the same and came up with yet another measurement from ruts in the ruins. Then someone from Greece did the same and in an ancient plaza that predates Roman times (by hundreds of years!) they found SOME measurements that actually were close to 4-ft 8.5-in, but many others that were quite different. This particular plaza was, in those ancient times, a market where it was forbidden to have Ox-carts in the plaza during the day when people were there shopping. So the plaza was re-stocked at night using torches to light the way. But the torches were not really bright enough so the cobble stone surface of the plaza was layed in such a way that there were trails that led past the vendor's stalls. There were even places where a cart could be directed into what would now be called a "passing siding" so the carts could pass each other. At any rate, the story of it being a Roman horse's backside is too modern a tale... it all likelyhood it probably was a Greek's Horse that set the measurement.


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## Ron Hill (Sep 25, 2008)

Just to add to what already has been said, Stephenson used a stock English locomotive using stock English rail when he started developing his standard railroad. Given how people hate to change, 4'-8 1/2" became America's standard gauge also. If the South had won the war, who knows, maybe 5'-0" might have become the standard. 
Ron


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## Dave Meashey (Jan 2, 2008)

I still think it goes back to the Egyptian charriots, and the dimension was originally 3 CUBITS! (That's my story, and I'm sticking to it. - Works out to each cubit being 18.83 inches.) 

Have fun, 
David Meashey


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## Greg Elmassian (Jan 3, 2008)

So JJ, why did you ask this question? 

(I think we have been here before!) 

Greg


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## Chris Scott (Jan 2, 2008)

Roman Chariots, Railroad Tracks, Milspecs, And Urban Legends : 
" ... the Roman army did not use chariots for warfare. Chariots were technologically obsolete by 600 BCE, centuries before the rise of Rome. While chariots were a technological leap when they came into use around 1800 BCE, they were far from the ideal weapon portrayed by Hollywood. Chariots were unstable and restricted in use to open and flat terrain. They were also expensive and difficult to make and maintain. The armies of the ancient world used chariots because the horses available to them were too small to carry a mounted soldier in armor and with weapons. Once horses were introduced that were large enough to carry a fully equipped soldier, cavalry quickly replaced charioteers. Cavalry was far more mobile, easier to maintain, and made more effective use of manpower since a chariot required a driver and fighter, whereas a single soldier could ride and fight on horseback.

The Roman legions that conquered the ancient western world were made up primarily of armored infantry supported by cavalry, light infantry, archers, and engineers. The Roman legions never used the technologically inferior chariot. Chariots were very popular in the Roman circus games and for ceremonial processions, but they were not used militarily or commercially. The suggestion that the Roman army developed a MilSpec for chariot wheel spacing that necessitated the placement of road ruts at 4 feet 8-1/2 inches is pure fiction. "


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## Dave Meashey (Jan 2, 2008)

"The suggestion that the Roman army developed a MilSpec for chariot wheel spacing that necessitated the placement of road ruts at 4 feet 8-1/2 inches is pure fiction. " 

*SEE!* I TOLD you it was the Egyptians, and it was originally 3 cubits!







(Just kidding! It most likely had more to do with the folks who manufactured hand-pushed coal wagons for mine tracks - and George Stephenson working with dimensions that he was familiar with.) 

Best, 
David Meashey


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## aceinspp (Jan 2, 2008)

So now that we all understand the how gage was determined why has JJ asked the question and what will he do with it. Later RJD


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## Semper Vaporo (Jan 2, 2008)

Posted By aceinspp on 09 Nov 2011 01:18 PM 
So now that we all understand the how gage was determined why has JJ asked the question and what will he do with it. Later RJD 

It also brings into question all those claims that he has a problem with train wrecks, since it seems it was everybody else that "Derailed" his thread!


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## work4fil (Jan 4, 2008)

Again, I am with Greg and still interested in what JJ is thinking. 

Fil


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## Torby (Jan 2, 2008)

@import url(/providers/htmleditorproviders/cehtmleditorprovider/dnngeneral.css); Posted By Dave Meashey on 07 Nov 2011 01:08 PM 
I still think it goes back to the Egyptian charriots, and the dimension was originally 3 CUBITS! (That's my story, and I'm sticking to it. - Works out to each cubit being 18.83 inches.) 

Have fun, 
David Meashey 
Oh wow. I never noticed that.

Yes! 3 cubit gauge!


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## kormsen (Oct 27, 2009)

Posted By work4fil on 09 Nov 2011 10:34 PM 
Again, I am with Greg and still interested in what JJ is thinking. 

Fil 

i think, JJ isn't thinking at all. (about the topic, i mean)

after having asked myself so many times, why he askes unusual but simple questions all the time, i resumed, that he is just doing his job as moderator.
he throws us bones to keep the pack busy.

at least that is, how it looks to me.


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## Greg Elmassian (Jan 3, 2008)

I'll agree that this is what it sometimes is. Other times, there's a reason. Courtesy would seem to provide an answer from the OP. 

Greg


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## John J (Dec 29, 2007)

It is a simple question

Is there a tolerance in the gauging?

Is it 4 FT 8 .5 inches Plus or minus Zero? Or plus or minus .5 inches or some other figure.


That is all I wanted to know. 


Korsman hit the nail on the head as to my motive. 


JJ


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## Semper Vaporo (Jan 2, 2008)

The tolerance varies according to the type of track. 
Mainline tangent (straight) is +/- 1/4 inch 
Yard tangent is +1/8 inch - 1/4 inch 

Curved track often (but not always) has a wider gauge, but the amount of extra gauge is determined by the class of the track (basically the speed it is designed to handle) and the type of cars are to pass over it at the designed speed. Back in the multi-coupled driver Steam Locomotive days the additional width was dictated on what curve radius the engine was capable of traversing at the desired speed (of course the gauge has a maximum value such that cars don't fall between the gauge. I have read (someplace) that the gauge might be widened by as much as 1 inch for sharp curves. 


EDIT:

I just found the following web reference:

http://tacnet.missouri.org/history/railroads/fra.html


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## aceinspp (Jan 2, 2008)

The web site listed is showing what FRA allows to be in compliance. However RRs do abide by the 4ft 81/2 inch rule. As we use to tell the RR inspecting folks you maintain your RR to your specks and not ours. At one point UP tried using a wider gage to see if it had any effect on track and equipment. well it got to the point when we ran the geometry car we gave them defects for wide gage. Talks about UP being up set. Now that was fun telling them they did not comply and need to correct. Kind of hurt there pride. Later RJD


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