New Sound Dampening System at Ashmont

http://onlinepubs.trb.org/onlinepubs/tc ... rpt_67.pdf

For those wishing to know more about noise reduction for wheels, see the above link for a technical report.

That reminds me...here's a shot of one of those sound dampening wheels at Everett.


By the looks of the mallet on the floor they were doing some in-house "testing".

Operators will tell you that they don't like a quiet streetcar. During the PCC era, they disliked the All-Electrics. Without air brakes and with rubber-sandwiched wheels, they were quiet. The only problem was that pedestrians were getting hit by them regularly because they didn't hear them coming.

3rdrail wrote:So you're telling us that your documentation was available yesterday publicly, but isn't now ?

Honestly, with all due respect, I'm beginning to wonder. We've gone from "dangerous" to "very, very annoying". Maybe it's not the noise that's very, very annoying.

No, you misunderstood. The link you gave is a presentation for the public. It takes screen caps from the full report. As far as I can tell, the full report is no longer available online. I didnt say it was there yesterday, I remember looking over it last year when the report was originally issued.


All I said was :
1) The loop was rebuilt, and with it, the sound went up
and
2) A study was done which determined that the noise level was dangerous (99db) and uncomfortable (the high frequency). The summary of this report is shown in the public presentation.

As such, the mitigation project began. No such projects have been done at other residential loops (like BC) because the noise level is different.

Remember, this is actually the THIRD attempt to lower the noise. The first was simple soundwalls, the second was a lubrication system for the entire loop.

Of course, The EGE was able to better explain why THIS sound is more annoying/relevant than other noises.

Also, fun experiment:
Find an older copper penny (1981 and older) and a newer zinc penny (1982 and newer).
Drop them both on a hard surface near you.
Can you hear the high pitched noise the copper penny gives off? If so, congrats, your ears aren't dead yet!

jamesinclair wrote:

3rdrail wrote:So you're telling us that your documentation was available yesterday publicly, but isn't now ?

Honestly, with all due respect, I'm beginning to wonder. We've gone from "dangerous" to "very, very annoying". Maybe it's not the noise that's very, very annoying.

No, you misunderstood. The link you gave is a presentation for the public. It takes screen caps from the full report. As far as I can tell, the full report is no longer available online. I didnt say it was there yesterday, I remember looking over it last year when the report was originally issued.


All I said was :
1) The loop was rebuilt, and with it, the sound went up
and
2) A study was done which determined that the noise level was dangerous (99db) and uncomfortable (the high frequency). The summary of this report is shown in the public presentation.

As such, the mitigation project began. No such projects have been done at other residential loops (like BC) because the noise level is different.

Remember, this is actually the THIRD attempt to lower the noise. The first was simple soundwalls, the second was a lubrication system for the entire loop.

Of course, The EGE was able to better explain why THIS sound is more annoying/relevant than other noises.

Also, fun experiment:
Find an older copper penny (1981 and older) and a newer zinc penny (1982 and newer).
Drop them both on a hard surface near you.
Can you hear the high pitched noise the copper penny gives off? If so, congrats, your ears aren't dead yet!

So, I've misunderstood aye ? So that I make sure that I understand, let me repeat again what you are telling us;

- (A) The new loop is noisier than the old.
- (B) A noise reading at the loop showed it to register 99 dBA.

As regards to "A" - Prove it ! I've produced documentation, let's see yours.
As regards to "B" - You are 100 % correct that a reading did show 99 dBA. However, what you suspiciously haven't told us is that this reading was pre-mitigation project - (by the way, it is still on the linked HMMH presentation - (page 7), in case you hadn't noticed it.) A post-mitigation project, more recent reading showed the reading to be 75-76 dBA(page 8, 9). (Also, by the way, a diesel bus seems to be 85 dBA and the inside of a NY subway train is 95 dBA [page 3]) (Sounds which are 10dBA less are considered half as loud. Sounds which are 20 dBA less are considered one-quarter as loud. source - HMMH) What this tells us is that a PCC car going around the Ashmont Loop is one-quarter as loud as riding in a New York City subway train.

http://www.mbta.com/uploadedfiles/About ... y%2020.pdf

My recommendation:
James, I have made statements which I stand by, and which HMMH backs up. Let's see some hard evidence in the form of documentation which does the same for your conflicting statements. In the meantime, give it a rest. Trying to prove your point by saying they wouldn't be doing it if it didn't need to be done, quite frankly is a little naive. There are a great many things that are done that don't need to be, and vice-versa, in the world of politics. Put another way, "Show me the money, baby !"

Could the results of the noise reduction efforts degrade over time - that is, could they be less effective after repeated usage? Perhaps the noise levels have increased again since July.

Of course anything is possible. However, if that is happening, I have not heard or read a word about it, so I can only assume that that's not the case. It's not applicable to Jamesinclair's argument, as his only articulable basis for it seems to be the 99 dBA reading which was an old reading made prior to the issue being addressed. A more recent reading showed the loop to read 76 dBA.

As I understand the "mitigation", it has been more topical than structural. I understand that a liquid such as windshield washer fluid was being used quite effectively. In any event, it may be a case of putting on a good show for the speculators from Sherborn who finally are assured that the Ashmont section is a "stable" neighborhood, want to move in to feel "the pulse of the city", but oh so hate to go from hearing crickets to streetcars. Theyll just have to soundproof their Volvos, I guess. Oh my !

3rdrail wrote: As regards to "A" - Prove it ! I've produced documentation, let's see yours.
As regards to "B" - You are 100 % correct that a reading did show 99 dBA. However, what you suspiciously haven't told us is that this reading was pre-mitigation project - (by the way, it is still on the linked HMMH presentation - (page 7), in case you hadn't noticed it.) A post-mitigation project, more recent reading showed the reading to be 75-76 dBA(page 8, 9). (Also, by the way, a diesel bus seems to be 85 dBA and the inside of a NY subway train is 95 dBA [page 3]) (Sounds which are 10dBA less are considered half as loud. Sounds which are 20 dBA less are considered one-quarter as loud. source - HMMH) What this tells us is that a PCC car going around the Ashmont Loop is one-quarter as loud as riding in a New York City subway train.

http://www.mbta.com/uploadedfiles/About ... y%2020.pdf

My recommendation:
James, I have made statements which I stand by, and which HMMH backs up. Let's see some hard evidence in the form of documentation which does the same for your conflicting statements. In the meantime, give it a rest. Trying to prove your point by saying they wouldn't be doing it if it didn't need to be done, quite frankly is a little naive. There are a great many things that are done that don't need to be, and vice-versa, in the world of politics. Put another way, "Show me the money, baby !"

I really dont understand what you're looking for.

The loop is new. It was built in a new location, and in a new configuration. Are you asking for proof that the loop was completely rebuilt? Because it's pretty common knowledge that the loop is probably newer than most of the complaining residents. I've said it three times, I'll say it again: I do not have the document showing the differences between the 2006 loop and the 2011 loop. Stop asking for it. I'm not trying to hide it, I can't find it on the MBTA website.


Right, the 99db is pre-mitigation.

Also, look at page 1 of this thread:
"Using noise meters from RadioShack, neighbors have measured the sound in excess of 110 decibels at the platform (louder than a jackhammer) and at 100 decibels in the kitchens of the Victorians, colonials, and three-deckers surrounding the station, with the windows open. The noise repeats every five to 12 minutes for 20 hours, from the first trolley at 5 a.m. to the last at 1 a.m."

Thats a valid concern.


And yes, the loop is less noisy than the new york subway. Except there's a giant difference between a loop in a residential neighborhood, and a train in a tunnel. I'm sure park street is louder than this loop. I'm sure the red line entering harvard is louder. Boylston is probably louder as well.

The difference is, those sounds are heard by passengers for 30 seconds at a time. The loop is heard by residents for the course of the day.

Again, I dont understand what point you're trying to get at here.

jamesinclair wrote:I really dont understand what you're looking for.

I'm only asking for your documentation, not anything mysterious or confusing.

jamesinclair wrote:No, the sound level went up with the new loop, because it's much tighter.

If you "do not have the document showing the differences between the 2006 loop and the 2011 loop", then how can you make the statement that it is noisier and "much tighter" ?

jamesinclair wrote:Right, the 99db is pre-mitigation.

Why didn't you happen to mention that it was "pre-mitigation" when you initially presented this fact ?

jamesinclair wrote:"Using noise meters from RadioShack, neighbors have measured the sound in excess of 110 decibels at the platform (louder than a jackhammer)...

Were you there ? Do you know the "neighbors" ? Are the "neighbors" objective and impartial ? Would they have anything to gain by falsely elevating noise results ? Are you a resident there ? So they used noise meters from Radio Shack, aye ? When were they calibrated ? Where ? Do you think that the apparently uncalibrated Radio Shack noise meters were of the same professional standard as the sound level meter that HMMH, a certified sound analysis corporation, used - a Bruel & Kjaer 2250 Sound Level Meter (Type 1) calibrated in the field and by Scantek, Inc. Calibration Laboratory on 9/11/09 ? Did the "neighbors" know how to use a sound level meter. Are the "neighbors" trained and have they performed these tests before ? Where ? You claim that the "neighbors" tests indicate a "valid concern" ? Are you kidding us ? Your argument is weak and your documentation has less substance than the Invisible Man.

I have no objective proof of this, but I grew up a few blocks from Ashmont (on the Radford Lane side of the station) and the old loop was also quite loud. I distinctly remember hearing from my house the squeal of the trolley wheels on the loop and the curve as the trolley left the station and headed toward Cedar Grove. Again, no scientific backing, but I was a good quarter mile away from the station and the sound could be piercing at times.

My sense is that this is a problem that predates the new loop, but that the new loop has exacerbated it-- because now the loop is closer to a quieter residential area rather than abutting Peabody Square.

This is not to say that the T shouldn't fix the problem, just that it goes back further than the new loop.

I agree with you, Midnight (good to see you back, buddy !) I only would add to the fact that the new loop is closer to single family residences as you suggest, that Dorchester is seeing a major influx of persons coming into the city from suburbs. Whereas persons enjoying their present home without thoughts of selling it are less likely to percieve a problem here, IMHP, I believe that the change from a relatively inactive housing market to an active one, has made the complaints louder and more often by more people. It's the old trick of looking for the scratch on the desk that you're buying at the flea market. That 1/2" scratch is not going to functionally affect your desk, but it could functionally affect it's price. I'm not buying it (in the figurative sense).

jamesinclair wrote: I've said it three times, I'll say it again: I do not have the document showing the differences between the 2006 loop and the 2011 loop. Stop asking for it. I'm not trying to hide it, I can't find it on the MBTA website.

If you cannot provide it, stop quoting it. If that evidence is gone, come up with new hard evidence, or lay off the sure sounding statements until you can.

If people focused this much attention on the money and resources being spent on keeping a section of track quiet, I'm sure that would cause another stir. I'm sure the same people that advocate low water pressure appliances (which greatly decrease their effectiveness) are the same people who were advocating spraying water on greasy tracks for 20 consecutive hours every day. Water, Money, and other resources are only precious and valuable when it's convenient. That's what gets me.

3rdrail wrote:
So they used noise meters from Radio Shack, aye ? When were they calibrated ? Where ? Do you think that the apparently uncalibrated Radio Shack noise meters were of the same professional standard as the sound level meter that HMMH, a certified sound analysis corporation, used - a Bruel & Kjaer 2250 Sound Level Meter (Type 1) calibrated in the field and by Scantek, Inc. Calibration Laboratory on 9/11/09 ?

Slightly off topic here in defense of the Radio Shack meters, the sound level meters are popularly used by audiophiles to test and balance their audio systems. Some audiophiles with access to professional sound meters and sound test equipment have tested the Radio Shack meters and found them to be very close to the pro meters in accuracy.

typesix wrote:Some audiophiles with access to professional sound meters and sound test equipment have tested the Radio Shack meters and found them to be very close to the pro meters in accuracy.

That's all nice and feel-good in pretend-land, but do the "audiophiles" have timely calibration documentation from a nationally certified laboratory saying that their Radio Shack sound level meters are accurate ? (Or is it a picture on the cover of the box of a twelve-year old kid saying, "this works great !") And, (once again) are the "neighbors" trained to use it ? Put another way, you can tell me that the streets of Boston are made of chocolate, but until I see a certified letter from Hershey's telling me the same thing, I ain't buyin' it !

Look folks. This is getting tiresome. Nobody on the "War Against Ashmont Deafness Committee" has been able to come accross with even one shred of real evidence to support their agenda - I mean theory. When you have something, let me know. Otherwise, frankly, I don't have the time to play silly games with immature people who don't understand that just because they heard something said, that it doesn't necessarily follow that it's true. That's why we rely upon accreditation and documentation. I'll let somebody else play make-believe for the time being.

I can't provide any technical quantification but, recently had to ride around the loop
over a hundred times, at varying speeds. I'm sure the abutters are not going to let
this matter rest as, the noise is of overwhelming volume and quality. I'm told that
the radius of the loop is smaller than its predecessor, a major factor. It is not however
smaller than loops formerly used elsewhere, by similar cars, on the Boston system.
I have recently been in a foreign city where PCC cars use very tight loops and, the
problem is relatively negligible. The only differences are, sound deadening wheels
as originally fitted to Boston cars, and traditional lubrication working on the
guard rails etc. I have consulted with one of the few manufacturers of PCC cars and
his opinion is that, resilient wheels, in spite of the added cost and maintenance
are an indispensable part of the package. Of the "Green" Lines, only the High Speed Line
loops in a residential neighborhood and only the PCCs have been retrofitted with
solid wheels so, it is a local problem for which a worldwide solution is known.
LS