We received this as humor in our email, and had seen it before so had some information about this. I have turned it into one of those why series of questions our children ask, that causes us to go look up the real answer, after we have flubbed our way through pixies and fairy dust, it is our formal duty to tell the truth.

The truth is, the United States standard railroad gauge (distance between the rails) is 4 feet, 8.5 inches. That is a rather odd number, your daughter might well ask: why was that gauge used?

It was because the first railways were built in England, and English were invited over to built the first American railroads. And, she may well ask, why did the English build them like that?

You have looked it up: the answer is because the first rail lines were built by the same people who built the earliest railroad tram tracks, and that's the gauge they used. Why did they use that gauge? Well, it seem that the men who built the tram tracks used the same wrenches, jigs and tools that they used for building wagons, which required that wheel spacing.

She says why did the wagons need that odd wheel spacing? you read some more, and find that it seems that if they used any other spacing, the wagon wheels would break,on the long distance roads in England. Why?
Because that's the spacing of the wheel ruts.

They were built by Roman legions and slaves from nearby, who created those now old rutted roads.Rome built the first long distance roads in Europe, and England, for their legions. The roads have been used ever since. So what about those ruts in the stone roads?

Roman war chariots formed the initial ruts, which everyone else had to match, or they would soon destroy their wagon wheels. As these chariots were made for imperial Rome, they were made all alike in the wheel spacing.

So, now, the United States standard railroad gauge of 4 feet, 8.5 inches is from from the original measurements for an imperial Roman war chariot, which was designed for a chariot with two horses side by side.

Bureaucracies live on forever. Maybe the next time you are handed a specification/ procedure/ process and wonder which horse's backside came up with this, you may be right on track. He or she is just on down the line.

Roman army chariots were made just wide enough to accommodate the backsides of two war horses. Remember this when you next see a space shuttle on the launch pad. You might give a thought of a Roman chariot, as there are two big solid booster rockets attached to the sides of the main fuel tank.

These are made at a factory in Utah. The engineers who designed these booster rockets knew they should be larger. But from Utah to Cape Kennedy these had to be shipped by train from the factory to the launch site.

As it happens, the railroad line from the factory needs to run through a tunnel in the mountains, and those booster rockets had to fit through that tunnel. The tunnel is slightly wider than the railroad track, and the railroad track, as you know, is about as wide as two horses' rumps.

So, this major space shuttle design feature of what is the world's most advanced transport system was made possible more than two thousand years ago by the width of two horse's backsides.

And now some people feel Washington is being governed by that same system and also by that same tunnel vision. We do not say that of course, but from the news, many are. Peace to us all; two horses rear width wide.

So, you thought nothing could come of being a horse's rear? Ancient horse's rumps still control a lot, and their human ancestors everything else, still for a while. Hold on, we are coming up to a tunnel. Hold your horse, by the you know where, no need to upset the chariot over every little change.