[USMA:22029] Re: Fwd: [A_A] "millimeter tolerance"

[Wizard of OS]

Title: Re: [USMA:22021] Fwd: [A_A] "millimeter tolerance"

hey Louis,, you're french, you should know best. Don't write km/hr! ----- Original Message ----- From: Louis JOURDAN To: U.S. Metric Association Sent: Tuesday, September 03, 2002 7:44 AM Subject: [USMA:22028] Re: Fwd: [A_A] "millimeter tolerance" At 17:33 -0400 02/09/2, [EMAIL PROTECTED] wrote: Although posted to a railroad list, this might interest the metric list as well. Note:  I replied that the inch is EXACTLY 25.4 mm, by definition. Carleton So it appears that the issue was not converting tolerances to Metric but that the SNCF MAINTAINS TGV LINES TO A TOLERANCE OF 1 mm!!!!  Incredible! What did the FRA find with CSX ("Route of the Pumping Ballast" proudly stencilled on box cars) the other year?  Tolerance of 1 *inch*?  For the record, there are about 25.4 mm in 1 inch.  Can you imagine *any* North American railroad maintaining track to this kind of tolerance?  Ha. The site is wonderful and really makes one *proud* to be American ... See http://mercurio.iet.unipi.it/tgv/ for TGV and http://mercurio.iet.unipi.it/ice/ for ICE info ... A total non sense. I would hope that Americans have other reasons to be proud... For the record, French TGV track tolerance is lower than 4 mm whilst conventional speed tracks, including the US ones, are maintained at 20 mm. See http://www.fra.dot.gov/rdv/volpe/pubs/techppr/errishft.pdf page 5-6. And this is an official paper from US government (all in SI, at least in dual units...) Please note, on page 10, a speed of 482 km/hr! Louis