Claim: The U.S. standard railroad gauge derives directly from the width of Imperial Roman war chariots.
Example: [Collected via e-mail, 2000]
The US standard railroad gauge (width between the two rails) is
Because that's the way they built them in England, and the US railroads were built by English expatriates.
Why did the English build them like that? Because the first rail lines were built by the same people who built the
Why did "they" use that gauge then? Because the people who built the tramways used the same jigs and tools that they used for building wagons which used that wheel spacing.
Okay! Why did the wagons have that particular odd wheel spacing? Well, if they tried to use any other spacing, the wagon wheels would break on some of the old, long distance roads in England, because that's the spacing of the wheel ruts.
So who built those old rutted roads? The first long distance roads in Europe (and England) were built by Imperial Rome for their legions. The roads have been used ever since. And the ruts in the roads? Roman war chariots first formed the initial ruts, which everyone else had to match for fear of destroying their wagon wheels. Since the chariots were made for (or by) Imperial Rome, they were all alike in the matter of wheel spacing.
The United States standard railroad gauge of
Now the twist to the story . . .
There's an interesting extension to the story about railroad gauges and horses' behinds. When we see a Space Shuttle sitting on its launch pad, there are two big booster rockets attached to the sides of the main fuel tank. These are solid rocket boosters, or SRBs. The SRBs are made by Thiokol at their factory in Utah. The engineers who designed the SRBs might have preferred to make them a bit fatter, but the SRBs had to be shipped by train from the factory to the launch site. The railroad line from the factory had to run through a tunnel in the mountains. The SRBs had to fit through that tunnel. The tunnel is slightly wider than the railroad track, and the railroad track is about as wide as two horses' behinds. So, the major design feature of what is arguably the world's most advanced transportation system was determined over two thousand years ago by the width of a Horse's Ass!
Origins: This item about the gauge of modern American railroads having been slavishly copied from the measurements of ancient Roman war chariots is a concept we've seen expressed well over a century ago, as exemplified by this nugget from a 1905 issue of Popular Mechanics:
So, rather than going into excruciating detail about the history of transportation, we'll simply note that roads are built to accommodate whatever uses them, and that for many centuries prior to the advent of railroads, what traveled on roads were mostly wheeled conveyances, pulled by beasts of burden (primarily horses), carrying passengers and goods. Physical conditions dictated some of the dimensions of those conveyances (such as the width of their axles) and largely ensured that they would fall within a fairly narrow range of variation: Horse-drawn vehicles, whether they were chariots or carts or carriages, all served similar functions, so practical considerations (e.g., the speed at which horses could travel, the amount of weight horses could pull, the number and arrangement of horses that could be controlled by a single driver) required that they be relatively similar in size as well.
That may suffice as an explanation covering the specific combination of horse-drawn vehicles and roads, but what about vehicles that traveled on rails instead of roads (such as trolleys), or that weren't pulled by horses (such as trains)? Why should they be similar in size to their predecessors?
Although we humans can be remarkably inventive, we are also often resistant to change and can be persistently stubborn (or perhaps practical) in trying to apply old solutions to new conditions. When confronted with a new idea such as a "rail," why go to the expense and effort of designing a new vehicle to use on it rather than simply adapting ones already in abundant use on roadways? Wouldn't it make sense to put the same type of conveyance pulled by regular horses on the ground behind an "iron horse" running along a rail? That is indeed what was tried in the early days of American railroads, as captured in the following illustration:
(The caption reads: "This locomotive in New York State, like its other early counterparts, pulled passenger cars based on old-fashioned carriages. The technology evolved quickly in the 1840s, however, and the United States played an important role in that evolution.")
Similar thinking occurred in Britain. Historian James Crow, writing about Housesteads, the
As for the Space Shuttle addendum to this piece, when Thiokol was building the solid rocket boosters (SRB) for the space shuttle, they had to keep shipping considerations in mind, but they didn't have to alter their design because any particular tunnel that lay between their plant and the Florida launch site wasn't large enough. Railroads don't run through tunnels only "slightly wider than the railroad track" unless every one of their engines and all their rolling stock are also only "slightly wider than the railroad track," and unless all tunnels encompass only a single set of tracks. Data from the U.S. Army's Rail Transport in a Theater of Operations document, for example, makes it fairly clear that one would be hard-pressed to find railroad equipment anywhere only "slightly wider" than
Over and above our love of odd facts, this tale about railroad gauges succeeds because of the imagery of its play on words: space shuttle technology was designed not by a horse's ass (figuratively, some overpaid government know-it-all) but because of a horse's ass (literally, the width of that particular portion of equine anatomy). People find this notion amusing, feeding the story's popularity as charmed readers continue to pass it along to others in a cascade of forwards.
"Very interesting, educational, historical, completely true, and hysterical"? One out of five, maybe.
Last updated: 14 January 2014
1. Ayers, Edward L., et al. American Passages: A History of the United States. Orlando: Harcourt College Publishers, 2000. ISBN 0-03-072573-9 (pp. 360-361). Black, Robert C. The Railroads of the Confederacy. Chapel Hill: Univ. of North Carolina, 1952. ISBN 0-8078-4729-1. 2. Crow, James. Housesteads. London: B.T. Batsford, 1995. ISBN 0-7134-6085-7 (pp. 33-34). 3. McPherson, James. Battle Cry of Freedom. New York: Oxford Univ. Press, 1988. ISBN 0-19-503863-0 (pp. 318-319, 514-515). Turner, George E. Victory Rode the Rails: The Strategic Place of the Railroads in the Civil War. Indianapolis: Bobbs-Merrill, 1953. ISBN 0-8032-9423-9. Weber, Thomas. The Northern Railroads in the Civil War, 1861-1865. New York: King's Crown Press, 1953. ISBN 0-2532-1321-5. Popular Mechanics. "Ancient Romans Determined Our Standard Railway Gauge." May 1905 p. 506.