AMA News: Executive Vice President - 2008/03
This is the end of the fiscal year, so I have no financial information to share. I do have a story that is interesting, though.
The historical chain
Why is the U.S. standard railroad gauge (distance between the rails) 4 feet 8.5 inches — an exceedingly odd number? The answer is a chain of historical decisions:
- Early U.S. railroads were built by English expatriates, so they used the same gauge that was used in England.
- Early English rail lines were built by the same people who built pre-railroad tramways, and they used the same gauge.
- Tramway builders used the same jigs and tools as wagon builders, so wagon wheel spacing determined tramway gauge.
- Wagon wheel spacing matched the ruts in long-distance roads in England; using a different spacing would break wagon wheels.
- Those long-distance roads were originally built by Imperial Rome for their legions.
- The ruts in those roads were formed by Roman war chariots, which all had the same wheel spacing.
The United States standard railroad gauge of 4 feet 8.5 inches can therefore be traced back to the specifications for an Imperial Roman war chariot. Bureaucracies and standards, once set, tend to persist.
Modern twist
Space Shuttle solid rocket boosters are made by Thiokol at its factory in Utah. Shuttle engineers preferred wider boosters, but the boosters had to be shipped by rail from the factory to the launch site. The railroad line runs through a tunnel that is only slightly wider than the track, and that track width was ultimately determined more than two thousand years ago by the spacing of a Roman chariot. In other words, one of the most advanced transportation systems in human history is constrained by a 2,000-year-old standard based on the width of two horses' behinds.
Thought for the day
Wear your expression proudly.
- A-B-C: Always Be Courteous.
Until later.
Transcribed from original scans by AI. Minor OCR errors may remain.
