Rider makes some noise about quieter BART cars
QI was riding in one of the new BART cars when I remembered that you reported a while ago that BART claimed they would be quieter than the old cars. So I downloaded a decibel meter to my phone and recorded sound levels while riding in the new car, and then later in an old car, sitting in the same seat location.
I was shocked to find that the results were virtually the same: new car average 84.3 dB (decibel), peak 102 dB; old car average 84.7 dB, peak 102.5 dB. What happened?
— Mike Domeniconi, Santa Clara
AJim-the-BART- Guy says he can’t speak to the accuracy of the decibel meter on your phone but says, “BART has been working for two years to transition its legacy fleet (the old cars) from the old cylindrical wheel to a new tapered profile that has been scientifically tested to reduce wear on the rails that is often referred to as corrugation. Riders are clearly noticing the difference. Noise complaints have fallen a whopping 73 percent
since the start of wheel reprofiling.”
He adds, “The new cars are designed to be quieter than the legacy cars. Grinding of the surface of the wheel has significantly decreased the noise level in all cars.
“Doors on the new trains use an entirely different technology than used by the current trains. Old BART trains have pocket doors that slide into the wall when they open. These doors contribute to a noisy ride because they do not adequately block noise from outside the train and they can rattle as the train travels through tunnels.
“The new doors utilize micro-plug door technology. This means they slide on a track outside the train, similar to a mini-van door. As they slide closed, they pull in three-fourths of an inch to seal tightly around the door frame. This plug dampens the amount of noise that reaches inside of the train, as well as providing better insulation, making the cars more comfortable on very hot or cold days.”
QGary, thank you for the column on peo
ple favoring high- speed rail. It was nice to have one entire additional column added to the funny pages. — Tony Lima, Mountain View
ANext to the funny pages?
QThere are plates over some expansion joints on the Fifth Avenue overpass on north Interstate 880 in Oakland. There is also one southbound before I- 980. Why are they there and when are they going away?
— Rick Magarian, Alameda
AThe metal plate on northbound I- 880 is under an emergency contract for a joint seal assembly repair. This assembly is currently being fabricated and the estimated completion for this job is around October. But the metal plate on southbound I- 880 is a maintenance job that is currently on hold.