I think those people opposed to the metric system get some kind of joy out of trying to misuse or abuse its structure. They hope by doing so they can make the metric system look "silly and useless", at least in their eyes. The tone of person's comment showed he was upset that Carleton prefers to use metric in that forum.
Jerry ________________________________ From: John M. Steele <[email protected]> To: U.S. Metric Association <[email protected]> Sent: Wednesday, February 25, 2009 8:14:53 AM Subject: [USMA:43257] Re: Mistaken blather from a correspondent on another list There is legislative precedent (or agency rules) that make clear if kilometers per hour were used officially for trains, it would be represented as km/h. NHTSA in FMVSS101 makes metric marking optional for car speedometers, but if used, it must be marked km/h. Similarly DoT in the MUTCD also allows road speed limits to be set in metric and mandates the units and marking as km/h. What Federal agency controls trains? I think it is DoT and their view is clear. I am not sure how many professional societies exist for the engineers who design locomotives (not the operators). The SAE is primarily automotive, but does have a group. They would certainly insist on km/h, thus if the locomotive's instrumentation were metric, it would be km/h. (SAE metric practice is SAE TSB003.) In calculations, it would certainly be appropriate to convert speed to meters per second for coherent calculations, but I don't know of any case where it is permitted as a vehicle speed indicator. Since the SI accepts the hour as a unit for use with the SI, it accepts kilometers per hour, even if it prefers meters per second. So the guy is remarkably wrong. Any idiot can make up any abbreviation he wants (who thought of lb. for pound), but when there is a correct symbol, it would be better if we all use it, just as it would be better if we all spell correctly. What is the value of taking the symbol used in the cab and rendering it unintelligible? --- On Wed, 2/25/09, Carleton MacDonald <[email protected]> wrote: From: Carleton MacDonald <[email protected]> Subject: [USMA:43256] Mistaken blather from a correspondent on another list To: "U.S. Metric Association" <[email protected]> Date: Wednesday, February 25, 2009, 12:54 AM On a passenger railroad-oriented list to which I also belong, an article was quoted which included mention of “kph”. I pointed this out, and received this reply from another list member who in the past has espoused very conservative opinions. Fire away, all. Carleton From: [email protected] On Behalf Of abyler Sent: Tuesday, February 24, 2009 22:47 To: [email protected] Subject: Re: [A_A] Full steam ahead for California bullet train --- In [email protected], "Carleton MacDonald" wrote: > > Also, the speed is expressed incorrectly - it should be "350 km/h" - there > is no such thing as a "kph". [his answer:] Sure there is. Its not like km/h is a normal SI measurement. The silly and useless SI Metric system would insist on us using m/s. kph is the colloquial Anglosphere abbreviation for kilmoeters per hour. Kilometers per hour is just a bastardized bending of metric system rules to accomodate something like a traditional customary speed measurement most people can relate to and actually use, just like the metric "pound" (= 1/2kg); "livre" in France, "pfund" in Germany, "pond" in the Netherlands and Flanders, "libra" in Iberia and Italy, "jin" in China; and the metric "ton" (=1000 kg); the metric cup (=250 mL); the metric teaspoon (=5 mL); the metric horsepower (750 kgf-m/s). See, that's the problem with the SI metric system compared to English customary units which is based on normal and practical human experience instead of esoteric physics. People cannot relate to the true SI metric units for most applications, so they don't use them. Just one more reason so many railways systems (and international aviation and shipping and meterology) have stuck with English units or older versions of metric where the units make more sense for engineering purposes and practical thinking by human beings.
