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We've heard from some of you about the noise that you hear while riding BART. Now there's some good news in the battle against noise: BART now has two state-of-the-art rail grinders.
"For years BART lived with one rail grinder," said Michael Brown, BART engineer. "It was sufficient to keep up, but with the growth of BART and the addition of more trains we need two to keep up and get ahead of the game."
The rail grinder is essentially a $4 million muffler designed to get rid of the ripples in the rails. During the day when BART train wheels pass over the rails, they cause microscopic ripples to form on the rails' surface. It's those ripples, called corrugation, that change the pitch of the noise BART trains make -- sometimes pushing the noise to irritating levels. While the loud noise isn't harmful, BART bought these custom-made machines to smooth out the ripples in order to provide a quieter ride.
"The ultimate goal is to get ahead of it to where we can fix the noise before it becomes a problem to our neighbors and patrons," Brown said. BART crews will use this newest grinder in combination with another new grinder that went into service in the fall of 2007. It's an impressive anti-noise armada compared with when BART had just one old grinder that was frequently in the shop for repairs.
"So we have less shuffling around with the machines and that's dead time not getting work done. The machines basically can grind more than the previous machine so just having one would give us more production."
Grinding the rails is just part of the critical work that's done in the early morning hours while BART isn't carrying passengers. Read more about what happens after-hours on BART and how you can still get around after midnight.