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BART cuts tube rail noise peaks from 95dB to 86dB

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  • 5/1 Bay Crossings
    Published Saturday, May 1, 2004, in Bay Crossings BART Quietly Makes Repairs By Guy Span Last September, Bay Crossings did an analysis of how loud was the
    Message 1 of 1 , May 6, 2004
      Published Saturday, May 1, 2004, in Bay Crossings

      BART Quietly Makes Repairs

      By Guy Span

      Last September, Bay Crossings did an analysis of how loud was
      the "swift, virtually noiseless and vibration-free electric train"
      (as BART was billed when built). At that time, we analyzed
      wheel/gauge profiles, rail grinding, and other causes of wheel–rail
      noise propagation. And while our engineers still believe that BART
      fails to open the gauge enough on curves (BART standard is 1/16" and
      real railroads are closer to 1/4" at a minimum), we did find one
      significant repair that BART has quietly made.

      According to spokesman Mike Healy, BART has recently run the rail
      grinding machine through the Transbay Tube. And that has really
      helped. We found the following improvements: ballasted straight track
      dropped two dB (decibels) to 68 dB, elevated curves dropped 8dBs to
      72 dB, tunnel curves dropped 4 dB to 78, and the biggest improvement
      was in the Transbay Tube, where previously there had been three
      locations with shrill screaming that topped 95 dB (ouch!) now reduced
      to 79–81 dB with a few spots briefly hitting 86 dB.

      The Occupational Safety and Health Administration (OSHA) has
      determined that the maximum sustainable level of noise in the
      workplace should not exceed 85 dB for a maximum of eight hours.
      So while your BART exposure won't hurt you, it still remains
      uncomfortably loud and not what Brian Stokes, the first General
      Manager of BART, promised us when he offered, "the swift, virtually
      noiseless and vibration-free electric train." Stokes also promised
      every rider would have a seat and that BART would eventually go to
      the airport. After spending $1.5 billion, which promise do you think
      was fulfilled? (Hint: Don't look for a seat on directional commute
      runs.)
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