But because of the design, one of the wheels ends up getting dragged against the rail on turns, which causes that high-pitched squeal. “So one wheel has to be sliding while the other is rolling,” Kolesar says.
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Testing has shown a drop of as many as 20 decibels in sound intensity. One way to think about the difference is if the decibel level of riding on a BART train with the old wheel profile and rail sounded like standing near a lawnmower the new system is more like being next to a dishwasher.
Noise. Many BART passengers have noted that the system is noisy, with a 2010 survey by the San Francisco Chronicle measuring up to 100 decibels (comparable to the noise level of a jackhammer) in the Transbay Tube between San Francisco and Oakland, and still more than 90 decibels in 23 other locations.
Rail corrugation (a periodic wear pattern resembling corrugated metal) causes tonal noise and vibration; fine, short-wavelength corrugation is known as roaring rails due to its high-pitched sound, whereas coarse, long-wavelength corrugation can cause the ground and nearby buildings to vibrate.
The reason that trains honk their horns so much at night is because it's dark and the trains aren't so easy to see. Even though the lights are on, you sometimes can't see them coming, especially around the many blind curves that Gilroy has, like the one near Leavesley and the one near the train station.
BART actually has a big machine that grinds down the bumps on corrugated track, eliminating some of the noise. This explains why sometimes a portion of the BART system makes loud uuunnnhhh sounds one day and doesn't make a peep the next. You aren't crazy -- they just smoothed out the track at night.
“People say BART cars are loud, but it's all relative,” Kolesar says. BART averages 35 mph, which is much faster than trains in most cities. New York's subway goes about half as fast on average — 17 mph. And as anyone who has taken the A train can tell you, New York subway cars are not known to be silent types.
BART has 8 DMU train cars which each have a seating capacity of 104. 70 mph maximum; 35 mph average, including 20-second station stops. For BART to Antioch DMU trains, the maximum speed is 75 mph; 60 mph average.
The majority of the old cars will be recycled. The Fleet Disposition Team will manage the process, including selecting which parts should be harvested from retired vehicles and choosing which cars with the highest failure rates get retired first.
Constructed in 57 sections, and reposing on the bay floor as deep as 135 feet beneath the surface, the remarkable $180 million structure took six years of toil and seismic studies to design, and less than three years to contract.
When it rains, BART also alters its computer programs to slow the acceleration of trains in certain areas to prevent them from spinning their wheels. But those delays, he said, are typically less than 30 seconds. It's nothing that would be noticed by passengers, he said.
He added: 'The Central line has the loudest section out of all of the tube lines, and it basically gets as loud as almost 110dB. ' The Jubilee, Central, Victoria and Bakerloo lines were also recorded to be louder than 105dB on ten different occasions.
This is the deep clean -- BART's all-out, every-nook-and-cranny effort to fight back against whatever the Bay Area throws at or into these trains. Every 400 hours we come in, Burditt explained. From top to bottom. Each car takes two people and about two to three hours to complete.
Q9: Will the new cars be faster? A: No.The new cars have a maximum speed of 80 miles per hour. To go faster than that, changes would need to be made, not only to the rail car propulsion systems, but also to other BART infrastructure.
As a safety feature to warn anyone crossing the line on foot/in a vehicle (or near the railway) that there was a train approaching them. This includes areas where shunting is being carried out (such as in a freight marshalling yard).