Over many years Geoffrey Laycock has written, and had published, upwards of 100 articles, some only a page long, others rather longer. A selection of them will be posted here if they are thought to be helpful, possibly amusing, or present a different viewpoint to the norm in health and safety.

If any material is used from this website please acknowledge its' source as Geoffrey A Laycock, The Otter Consultancy, www.otterconsultancy.co.uk  We hope some of it is of value to you.

Always Ask Why (first published 1999)

I was recently putting together material for training engineers in ‘plant change management’ and wanted several slightly unusual examples to illustrate a few points.  One of those examples was the explosion at launch of the space shuttle Challenger in 1986.  Having prepared that material I happened upon some other interesting facts connected with that incidents, including a rather unusual explanation of why the solid-fuel rocket boosters (SRB) were the diameter they were. 

Those who know me are more than aware of my love of the word ‘why’, a word that should be used far more often by people in connection with safety.  Here is a slightly more amusing result of using it.

The US Standard railroad gauge (distance between the rails) is 4 feet, 8.5 inches. That's an exceedingly odd number.  Why was that gauge used? Because that's the way they built them in England, and the US railroads were built by English expatriates.

Why did the English people build them like that? Because the first rail lines were built by the same people who built the pre‑railroad tramways, and that's the gauge they used.  Why did  "they" use that gauge, then?  Because the people who built the tramways used the same jigs and tools that they used for building wagons, which used that wheel spacing.

Why did the wagons use that odd wheel spacing? Well, if they tried to use any other spacing the wagons would break on some of the old, long distance roads, because that's the spacing of the old wheel ruts. So, who built these old rutted roads?  The first long distance roads in Europe were built by Imperial Rome for the benefit of their legions.  The roads have been used ever since.

Why the ruts? The initial ruts, which everyone else had to match for fear of destroying their wagons, were first made by Roman war chariots. Since the chariots were made for or by Imperial Rome, they were alike in the matter of wheel spacing. Thus, we have the answer to the original questions - the United States standard railroad gauge of 4 feet, 8.5 inches derived from the original specification for an Imperial Roman army war chariot, specified over two thousand years ago.  They were that wide because the Imperial Roman chariots were made to be just wide enough to accommodate the back‑ends of two war horses.

So what does that have to do with the Shuttle solid-fuel rocket boosters?

When we see a Space Shuttle sitting on the launch pad, there are two booster rockets attached to the sides of the main fuel tank.  These are the solid-fuel rocket boosters, or SRBs.  The SRBs are made by Thiokol at a factory in Utah.  The engineers who designed the SRBs might have preferred to make them a bit fatter, but the SRBs had to be shipped by train from the factory to the launch site. The railroad line to the factory runs through a tunnel in the mountains. The SRBs had to fit through that tunnel.  The tunnel is slightly wider than a railroad track, and the railroad track is about as wide as two horses' behinds. So a major design feature of what is arguably the world's most advanced transportation system was determined by the width of two horse's backsides.

All I did was ask why?        ADDITIONAL THOUGHT - How often have you asked someone at work 'why do you do it like that?' and not had any sensible answer? Start asking now, it's a wonderful way to start risk assessments.