The rail gauge in the United States is 4 feet and 8 ½ inches. But why this measure?

The answer is very simple. They have that measure because that’s how they did it in Great Britain and the first American rail gauges were built by British engineers.

And why did British built them?

Because the first rail gauges were built by the same people who built the first tramways, and that’s the gauge measure they used for trams.

And why did trams use that measures?

Because to make the tram tracks they used the same template and tools that they used for building carts and carriages, which had that space between the wheels (4 feet and 8 ½ inches).

Why did carriages use that distance between wheels?

Because if they had used other measures the carruages’ wheels would have broken in English roads where ruts were marked, since the distance between the wheels of a cart was this standard measure and other measures would have broken carriages.

And who wanted to make the old narrow roads where ruts were marked by carriages passing always in the same place?

Well, it is known that all long distance roads in Europe were built by the Romans for their legions.

So the ruts…

Ah! The first ruts were formed by the chariots of the Roman legions, which had all the same space between the wheels.

And we are as before. And why exactly that measure?

Well, you should have asked me before! The 4 feet and 8 ½ inches measures derived from the standard Roman chariot measure, which corresponds to the width of two horses.

The width of two horses stablished the pattern that Romans took to build their chariots and hence the width of the rail gauges in the U.S.

American rail gauges. Photo by Vilseskogen