I don't know why the Russian chose to use a different gauge to the rest of Europe, but according to this reference (http://home.fonline.de/fo0126/geschichte/groessen/mas13.htm#ank2 German language) the Russian foot was the same as the English foot. The Russians adopted the metric system in 1917, but their railway system predates this. The article in Wikipedia (http://en.wikipedia.org/wiki/Rail_gauge) suggests that am American engineer who assisted the Russians in 1842 was responsible for using the 5 ft gauge (which apparently was common in the Southern US states).
-----Original Message----- From: John Frewen-Lord [mailto:[email protected]] Sent: 08 March 2009 20:17 To: [email protected]; U.S. Metric Association Subject: Re: [USMA:43526] Re: Metric discussion on the railroad list (1) Standard guage all over the world is 1435 mm. However Russia (and the old USSR, as well as some satellite states such as Finland) used - quite why for totally metric countries - a gauge of 5' 0" (1520 mm). Ostensibly that was to preserve Russian sovereignty by preventing through running of trains from Western Europe. I do not know however quite why an imperial dimension was used in a totally metric country. Does anyone know the answer to this? ----- Original Message ----- From: "Martin Vlietstra" <[email protected]> To: "U.S. Metric Association" <[email protected]> Sent: Sunday, March 08, 2009 8:10 PM Subject: [USMA:43526] Re: Metric discussion on the railroad list (1) > > The US standard rail gage was derived from the British standard gauge of > 4ft > 8½in (1435.1 mm). However the Irish works out in round numbers in both > metric and imperial units - 1600 mm differs from 5ft 3in by 0.2 mm - well > within tolerance limits. > > -----Original Message----- > From: [email protected] [mailto:[email protected]] On Behalf > Of John M. Steele > Sent: 08 March 2009 16:34 > To: U.S. Metric Association > Subject: [USMA:43495] Re: Metric discussion on the railroad list (1) > > > > Assuming Wikipedia is correct, the tolerance of 1435 mm gauge track is > 1423 > mm to 1460 mm for track rated for 60 MPH travel. I assume lower grade > (lower speed) track is allowed a wider tolerance. Thus, that 0.1 mm > confusion in nominal is entirely negligible. > > I assume the tolerance is asymmetric because the width can not be narrower > than maximum wheel flange spacing (the flanges are on the inside, and > ideally do not touch) > http://en.wikipedia.org/wiki/Rail_gauge > > > --- On Sun, 3/8/09, Jeremiah MacGregor <[email protected]> > wrote: > >> From: Jeremiah MacGregor <[email protected]> >> Subject: [USMA:43489] Re: Metric discussion on the railroad list (1) >> To: "U.S. Metric Association" <[email protected]> >> Date: Sunday, March 8, 2009, 11:53 AM >> Carleton, >> >> > Also in the design of railroad equipment, can you tell us >> what the usual tolerance ranges usually are? You are >> correct that in the world they don't get precise to >> sub-millimeter precision unless they have to. They would >> round everything to whole numbers if it wouldn't effect >> the outcome or if it falls within acceptable tolerances. >> >> The standard rail gage in the US is 56.5 inches, which >> equals 1435.1 mm. Everywhere else it is equal to exactly >> 1435 mm. I don't know anything about railroads but I >> bet that nowhere will one find the tracks consistently 1435 >> mm due to many factors that distance will vary to some >> degree. There is constant exposure to heat and cold. >> There are movements in the earth which can shift tracks, >> etc. Thus to worry about sub-millimeter lengths is >> ridiculous. >
