Why is the standard railroad gauge in the United States 4 feet 8.5 inches?

gmackematix

Partly due to borrowing of engines from the UK. Then convergence to a standard gauge became necessary with the increase in equipment exchange and was hastened by the destruction of the south's broad gauge during the American Civil War. http://en.wikipedia.org/wiki/Standard_Gauge Nov 13 04, 11:18 PM

kaylofgorons

That's also correct. My puzzle is this, why 4 feet 8.5 inches? Why not 5 feet? or 4.5 feet? Where did the UK get the measure from? Where does this strange measure come from? I have a source of unknown reliability that gives a specific origin... :) Anyone know? Nov 14 04, 12:09 PM

Stew54

I'm guessing that your source refers to the similarity between the gauges of modern railways and earlier horse drawn transport, possibly using the example of a Roman chariot. You might find this page helpful: http://www.snopes.com/history/american/gauge.htm Nov 14 04, 12:30 PM

kaylofgorons

Yay! Romans built the first long distance roads in England, for their chariots and such. The distance between wheels was about 4 feet 8.5 inches. When others would use these roads, their wheels had to fit the ruts left by the Roman war chariots, so all wheeled transport was made to fit. When they built the first tramways, they used the same measure, and it just kept going from there! Bonus trivia fact: The booster rockets on the Space shuttle had to fit through a narrow train tunnel to make it to the launch pad. Therefore our most advanced transportation to date was limited in size by the width of a horse-drawn chariot! Nov 14 04, 1:01 PM

Baloo55th

There are grave doubts about the Roman connection. When the Romans went and the Saxons etc came in, a lot of the roads went into disuse as the new population was far more country based than town based, and the roads linked the Roman towns built around the camps. By the time the roads system was redeveloped, there wouldn't have been many Roman ruts left - especially as they paved a lot of road surface anyway. It's hard to see medieval wainwrights being that standardised. The need for standards only came in with the first plate railways - where the rail was an L shape with cart wheels running inside the uprights. Precision wasn't all that important here, but was when the flanged wheel running on top of the rail was introduced. According to http://www.curator.pwp.blueyonder.co.uk/news.htg/issue44/railways.htm the width was intended by one of the earliest constructors to be 5 foot, with the flanges on the outside. However, he realised this wasn't practical, and changed to inside flanges but kept the rails the same distance apart - which gave the current standard gauge. Nov 14 04, 1:57 PM