Thursday, December 20, 2007

Today’s 10 minute history lesson: Railroad tracks.


Here’s a question (maybe not a particularly interesting question on the face of it, but a question nevertheless) that you probably have never considered before. Why are the rails on American railroads such an odd distance apart (4 ft, 8 ½ inches or 1435 millimeters)? That seems a very unusual number. Why couldn’t whoever came up with that use a more round number? If nothing else, it would seem that a round number for the track gauge would make it easier for people to remember and to more easily set measuring tools.

You have probably guessed that I would not ask such an odd question without being ready to divulge the answer. So, here it is.

- The American railroad system has its origins in the English railroad system and, therefore, each use the same gauge of track.

- The English railroad system, when in its infancy, didn’t have a large manufacturing base ready to churn out larges amounts of railroad equipment. It was much easier to adapt other equipment that was readily obtainable. These were, of course, the horse-drawn wagons and coaches of the day, and those wagons and carriages had this odd standard for their wheel measurements. The early English manufacturers of railroad equipment just kept the wheel gauge the same, as it was far easier that way. They only had to remove the wagon wheels and install flanged railroad wheels on the same axle system. This became the standard wheel gauge for early English railroads.

- The wheel measurements on the wagons and carriages came from the fact that many of the roads in England were paved in stones. After long periods of use, the stone paving starts to exhibit wear patterns in the form of groves in which the wagon wheels fit. Thus, it became the standard to make wagons and carriages with this measurement so that they would easily fit into the groves worn into the roads. Anything else besides that distance between the wagon wheels would have made a wagon almost unusable on heavily traveled paved roads.

- A very large number of wagons in England were imported from Rome, during the Roman occupation of England (approximately 40 A.D. to 400 A.D.). This was the standard for the Roman army, and later became the standard for civilian wagons and carriages in early England. The Romans, of course, brought to England the same types of carriages and wagons they used in Italy and the rest of their empire.

Thus, the inescapable conclusion of this historical trail is that American railroads use a very odd standard for the gauge for their tracks is because ancient Roman wagons and chariots were built with that gauge. Ben Hur to the Union Pacific.


UPDATE: From the comments, Wolfman (good buddy that he is) pointed out that I missed the last link in the logical chain. The width of Roman wagons and chariots was set not by some ancient craftsman just picked that width because he liked it. No, the width of the Roman wagons was set because that's the width of two horses butts, standing side by side. Now, THAT'S history.

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