The Straight Dope | The Straight Dope | Chicago Reader

The Straight Dope 

Sign up for our newsletters Subscribe

I recently was sent this interesting story by an Internet friend. Is this true?

--Dave Shorr

Dave attached the following message, the sort of cyber-folklore that frequently makes the rounds on E-mail:

"The U.S. standard railroad gauge (distance between the rails) is four feet, eight and a half inches. That's an exceedingly odd number. Why was that gauge used? Because that's the way they built them in England, and English expatriates built the U.S. railroads.

"Why did the English people build them like that? Because the first rail lines were built by the same people who built the prerailroad tramways, and that's the gauge they used.

"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.

"Why did the wagons use that odd wheel spacing? Well, if they tried to use any other spacing the wagons would break on some of the old, long-distance roads, because that's the spacing of the old wheel ruts.

"So who built these old rutted roads? The first long-distance roads in Europe were built by Imperial Rome for the benefit of its legions. The roads have been used ever since.

"And the ruts? Roman war chariots made the initial ruts, which everyone else had to match for fear of destroying their wagons. Since the chariots were made for or by Imperial Rome, they were all alike in the matter of wheel spacing. Thus, the standard U.S. railroad gauge of four feet, eight and a half inches derives from the specification for an Imperial Roman army war chariot.

"Specs and bureaucracies live forever. So the next time you are handed a specification and wonder what horse's ass came up with it, you may be exactly right. Because the Imperial Roman chariots were made to be just wide enough to accommodate the back ends of two warhorses."

Funny? Sure. True? Yes and no. Sorry for the wishy-washy answer, but follow the whole line of development and you'll see what I mean.

(1) U.S. track gauge based on UK track gauge. True. While most U.S. railroads were designed by U.S. engineers, not British expatriates, a number of early lines were built to fit standard-gauge locomotives manufactured by English railroad pioneer George Stephenson.

(2) UK railway track gauge based on width of earlier tramways used to haul coal. More or less true. Although tramway width varied widely among regions, those in the coal district in the north of England, where Stephenson began his work, used a gauge of four-foot-eight.

(3) Northern England tramway width based on wagon-wheel spacing. Not literally true; there was no standard wagon-wheel spacing. However, wagons and their wheels averaged five feet in width, since this size would conveniently fit behind a team of draft animals. The northern England tramway gauge apparently had been arrived at by starting with an overall track width of five feet and using rails that were two inches wide. Five feet minus four inches for the rails equals four-foot-eight. (I'm skipping some complicated history here, but that's the gist of it.) Stephenson later widened the tracks a half inch for practical reasons, making the standard gauge four feet, eight and a half inches. While this is an "exceedingly odd number," it derives from a basic track width of five feet, which is not odd at all.

What about Roman war chariots and rutted roads? Roman "rutways," many of which were purposely built to standard dimensions, were close to modern railroad tracks in width. For example, the rutways at the buried cities of Pompeii and Herculaneum averaged four-foot-nine center to center, with a gauge of maybe four-foot-six. But there's no direct connection between Roman rutways and 18th-century tramways. The designers of each were dealing with a similar problem, namely hauling wheeled vehicles behind draft animals. So it's not surprising they came up with similar results.

Art accompanying story in printed newspaper (not available in this archive): illustration/Slug Signorino.

Comments

Subscribe to this thread:

Add a comment

More by Cecil Adams

Agenda Teaser

Performing Arts
Bus Stop Athenaeum Theatre
July 19
Music
Drake, Migos United Center
August 17

Tabbed Event Search

Popular Stories