It's just a thought, but maybe instead of relying on the "viewpoint" of a "BART rider", or on the voices coming through Mouse's tinfoil hat, maybe, somebody should collect decibel exposure "data", by using a decibel meter, to do a sampling of 30 runs on new cars, and 30 runs on old cars, and determine the difference in the two sets of decibel level data...?

Then, we'd really know, using the miracle of the "scientific method" and "math", if the new cars are a) noisier, b) the same, or c) less...right? And, even what the average difference likely is...

Back when they paid me to do things like this, that's what I'd have had a couple of the interns out doing, for a day... go collect actual "data"... They seemed to pay me more for actually knowing the answer, than for speculative conjecture, or referencing unverifiable comments from one rider, as to what the real answer might be... But, maybe that's just me being too "old timey" about that kind of thing, again....