BART rail grinding puts it among quietest rail systems in nation

Written by jrood

Steel on steel plus speed equals noise. No doubt about it - sometimes a ride on BART can be noisy. If you've ever tried to hold a conversation going through the Transbay Tube, you know it can be difficult to hear.

But, believe it or not,
BART is rated one of the quietest transit systems in the nation. And efforts
are constantly ongoing to provide a quieter ride for passengers.

The sounds of BART were in
the news Sept. 7 after a San Francisco Chronicle article in which a reporter
traveled the 104 miles of BART’s rail system with a handheld decibel counter,
measuring noise levels. (BART does its own similar measurements
routinely.)  Hearing experts, as
well as the Chronicle article, have noted that while decibel levels on BART at
any one point in time might clock in at a high level – comparable to hearing a
jackhammer at a construction site – it would typically take a sustained
exposure over many hours’ time to reach a level of actual harm.

Linda Horwath, program
coordinator for a group called Dangerous Decibels, told the Chronicle: "We
talk about your sound exposure over a whole 24 hours. If you have a fairly
quiet day and get on the subway and have a few minutes of 90 decibels or even
100 decibels, you’ll be fine."

The National Academy of
Sciences’ Transit Research Board sponsored an independent study in the 1990s to
look at rail sound. The study concluded, "With trued wheels and smooth
ground rail on ballast and ties, BART is one of the quietest vehicles in
operation at U.S. transit systems."

BART Chief Communications
Officer Linton Johnson said that according to the report, "You’d be hard
pressed to find a quieter system" anywhere in America."

Johnson also noted BART is
the only transit system in North America with two rail grinders and three wheel
lathes, with a fourth lathe in the works. These machines help grind down the
tiny ripples on the tracks that cause the screeching sound when they come into
contact with moving wheels.

"We’ve made an
investment in two multi-million-dollar mufflers called rail grinders,"
Johnson said, adding that the problem spots for noise tend to be on curves and
inclines.

BART monitors sound levels
in part for the benefit of employees such as train operators, who necessarily
must be exposed to the sounds for longer periods as part of their jobs. They
help cope by wearing earplugs at times for sound protection, which may be a
tactic for passengers who are sensitive to sound as well.

Riders are urged to be
cautious about another common cover-up for rail sounds – listening to music on
earbuds. It’s a popular way to pass the time, but hearing experts warn that it
just ends up exposing your ears to even more noise throughout the day. And
those who listen at volumes so loud that the music can be heard outside their
headphones get into another problem area – annoying their fellow passengers,
who may not share the same taste in music.

To view the original story, please visit www.bart.gov.

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