BART cuts tube rail noise peaks from 95dB to 86dB
- 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 wheelrail
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 7981 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