I’m throwing the BS flag again. And, if you’re a betting man I’ll call your gee-go-guarantee for the price you name. If you actually lay a turnout using the maximum track gauge, I will guarantee derailments as the wheels consistently pick the frog with guard and wing rails set at the correct check gauge. For whatever reasons, the NMRA wheel gauge is narrower than the track gauge - they don’t match as they should. In most scales/gauges, the discrepancy is about 1.5 scale inches, in HO it’s actually more. Because of this, those in the know who handlay turnouts lay them to MINIMUM track gauge throughout. And these turnouts perform flawlessly. For futher discussion of the issue, see http://groups.yahoo.com/group/handlaidtrack/ and http://www.railwayeng.com/rrhints.htm Take a micrometer or calipers to your NMRA gauge for personal verification that the “track” and “wheel” gauges are different.
In the meantime, you lay your turnouts to maximum gauge, and I’ll lay mine to minimum and we’ll count our derailments…
THINK I’LL START BUILDING MY NEXT SWITCHES TO YOUR STANDARDS INSTEAD OF NMRA STANDARDS! I HAVEN’T HAD A GOOD DERAILMENT IN MANY YEARS - EXCEPT ON COMMERCIALLY MANUFACTURED SWITCHES!
TOMORROW I’M GOING TO MAKE A STATEMENT THAT THE EARTH IS ROUND. WHOSE GOING TO PICK A FIGHT WITH ME OVER IT???
While all this talk of abstraction and minimum and maximums is all very interesting and erudite, if you look carefully at the diagram for Standard 3.2 of the NMRA, you will note that distance G, the track gauge, which has both acceptable minimum and maximum values, is measured between the inside, facing surfaces of the two rails. No abstract thinking needed: just careful observation of a diagram put there to make the abstract easy to understand.
FYI, per the www.truthorfiction.com website, the roman chariot story is fiction. Here’s the real deal according to them:
"Where did the four-foot, eight-and-a-half-inch standard originate? Gabriel says it was from a Englishman named George Stephenson. Carts on rails had been used in mines in England for years, but the width of the rails varied from mine to mine since they didn’t share tracks. Stephenson was the one who started experimenting with putting a steam engine on the carts so there would be propulsion to pull them along. He had worked with several mines with differing gauges and simply chose to make the rails for his project 4-foot, eight inches wide. He later decided that adding another six inches made things easier. He was later consulted for constructing some rails along a roadway and by the time broader plans for railroads in Great Britain were proposed, there were already 1200 miles of his rails so the “Stephenson gauge” became the standard.
Interestingly, the 4-foot, eight-and-a-half inch width has not always been the standard in the U.S. According to the Encyclopedia of American Business History and Biography, at the beginning of the Civil War, there were more than 20 different gauges ranging from 3 to 6 feet, although the 4-foot, eight-and-a-half inch was the most widely used. During the war, any supplies transported by rail had to be transferred by hand whenever a car on one gauge encountered track of another gauge and more than 4,000 miles of new track was laid during the war to standardize the process. Later, Congress decreed that the 4-foot, eight-and-a-half inch standard would be used for transcontinental railway."
Another excellent demonstration of why the distance is measured between the rails - ever see just how many variations in rail head profile there have been over the years? The width of the rail head is not a universal standard. The gauge is. That’s why a loco that was built to run on fishbelly profile cast iron rail (eg - “John Bull”) will happily run on modern rails.
Incidentally, standard gauge was originally 4’8" in Britain. The half inch was (as I recall) added some time in the 1820s-30s to prevent binding on curves.
Then you’ll end up with track that no standard gauge rolling stock will be able to run on.
The gauge is ALWAYS measured inside the railhead. Dunno what engineering drawings you work from but I wouldn’t want to be on any standard gauge track that originates from that drawing office.
I have worked on the steel gang and believe me, it’s the inside measurement, every time, no exceptions, period!
Because the widths of the tread surface on the heads of rails varies over time and road, measuring to the centres, even in a road that has a particular pattern, will result in errors greater than if the measurement was taken at the flange surfaces of the heads, or the insides. Measuring to the insides is controllable with only one dimension, while dealing with track widths adds another order of EOM (error of measurement).
Exactly. I tried to say that, but it didn’t work. I had a thought once about the 4 feet 8 and a half. I think I read that an early shot at wheel on rails put the flanges on the outside. It wasn’t long before it was realized this was clearly the wrong way to go, so they flipped the flanges to the inside. Now the part I’m making up. Say this was England, and they started out with track that was pretty narrow (maybe a little under two inches), layed them with an outside gauge of a nice even five feet. When they flipped the wheels, they wouldn’t have wanted to change the track, so by total happenstance, the onside gauge was on the order of 56.5 inches, and a standard was born. Please remember, I made this up, I have no basis for this except my own imagination, and some experience in making lemonade from lemons.
Indeed–these folks who claim “center of rail to center of rail” are assuming that all rail is the same width–obviously, not all rail is of equal width, which would mean that differing sizes of rail results in different distances between the inside of the rails–and the inside of the rails are where the flanges of the wheels are! If the flanges of the wheels don’t fit between the rails, Bad Things tend to happen.
INSIDE RAIL TO INSIDE RAIL. It’s more than just a good idea…it’s the law!
“Center of rail to center of rail” measurements have nothing to do with why there’s a gauge measurement in the first place, which is keeping the wheels on the rails at all times. Any source which purports to define track gauge as a center to center distance is wrong, period. If these “experts” spent some time reading up on what check gauges, back to back wheel distances, track gauge, and other RELEVANT measurements had to do with preventing derailments, there’d be less nonsense promulgated as gospel.
Or alternatively, they could work on a track gang, and find out how the important distances are measured in the real world. Any railroad operation would do, common carrier, museum railroad or other. Or just look carefully at a track gauge used by the real world operations: the gauging surfaces contact the inside surfaces of the rails, they don’t try to find the centers of the railheads.
For that matter, if they measure the dimensions of an NMRA gauge, they’ll quickly find what distance on the gauge corresponds to the distance G (track gauge) in the standards.
All THIS just because poor Electrolove asked ONE SIMPLE question!! Electrolove, you see why you get things done in Sweden and it takes us an entire committee of 10,000 to answer one question? LOL
The Railroad: What It Is, What It Does by John Armstrong
A book long used as a reference by professional railroaders, which includes the diagram shown by the San Diego Railroad Museum
and the beginner’s guide to DTG (Digital Track Gauge) available at the following site http://www.graw.com/angielski/dtg-1435-en.htm
By clicking on the image of the beginner’s guide on the linked page above, you can download a guide to using the Graw Company’s state of the art, digital track gauge. Look at page two of this guide and take note of what surfaces are being measured when you measure track gauge with this device.
I hope these additional resources are equally funny.
GearDrivenSteam wrote: <“I’ve always thought that the measurement was taken from the center of the top of the rails. Seems like that would make the most sense.”> Does it? Why? What you’re saying makes no sense at all. Think about it for a moment - where do the flanges ride? Between the gauge faces or on top of the rails? Mark.
modlerbob wrote: <" In the 1:1 scale world the 4’-81/2" distance is from center of rail to center of rail, at least on the engineering drawings I work from. "> Sounds like utter BS to me. What engineering drawings are you claiming show the gauge from centre to centre? Care to post an example? Mark.