When you next see a Space Shuttle on the launch pad have a look at the SRB’s (Solid Rocket Boosters) attached to it. These are made in Utah by Thiokol and the designers may well have liked to make them bigger, but as they had to be moved by train from the factory to the launch site the designers were restricted in their dimensions by the dimensions of the tunnels they had to pass through.
US rail tunnel dimensions are dictated to by the width of the train and this is dependent upon the railroad gauge which is 4’8 ½” inches between rails, about 143.51 centimeter. To say this is an odd figure is an understatement, so why was that dimension used?
Simple, this is because the first railways in the USA were built by British expatriates who brought over their jigs and tools with them. They first used these for the horse drawn wagons, then they used them when they built the railways.
Why did the British use that spacing? Easy to answer! When they started building horse drawn transport in Britain they had to use that 4’8 ½” spacing because to do otherwise would destroy their wheels because they would not match the ruts that were already there in most of the old, already existing roads.
Who or what made those existing ruts in Britain’s old roads? They were made, around 2000 years ago by the Romans.
There then is the answer. Over 2000 years ago someone decided to measure the hindquarters of two horses and decided on the wheel spacing of 4’8 ½” because it was the perfect dimension for a war chariot. So a major design feature of one of the world’s most advanced transportation system, the SRB's on the space shuttle, was in fact determined over 2000 years ago by someone in a stable measuring a horse.
And around 2000 years ago something else occurred in a stable that also determines many lives of today...