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 Tuesday 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. (Download the Transit Cooperative Research Program's report 6.62 Mb .pdf)
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 multimillion 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.
Find out more about what BART is doing to keep the sound down by watching this video on BARTtv.
Updated with new detail September 7, 9:24 a.m.