Slashdot Mirror
MagLev Trains Annoyingly Loud
crem_d_genes writes "You might hear that whistle blowing from that train coming 'round the bend, but tapes of the sounds produced by magnetically levitated and normal trains produced a result that was something of a surprise: Most people rated maglev trains as more disturbing than standard intercity trains. It had been previously known that the two types were about equally loud, but this study analyzed people's reactions to them. Since the effects on the environment will be part of the feasibilty studies for future development, acoustical engineers will have some new challenges. Some participants in the study said the sound made them 'feel insecure, some found it startling, and disliked the occasional shrill sound the maglevs produced.' The researcher postulated that unfamiliarity with the noise might be part of the problem."
Does anyone know of links to audio samples of a maglev? I've never heard one and some rudimentary googling didn't turn them up.
The quality of the noise source is as important as its intensity (i.e. decibels). Some noise patterns are just plain annoying. For instance, in noise studies, helicopters are considered more annoying and have lower acceptable decibel thresholds; the old Hueys are a prime example.
I want to hear the sound for myself! (Preferably without having to visit one of the trains in person.)
Can anyone explain this to me about um... "traditional" train sound, because I've always wondered: Why are they so loud at night? I know trains run through the city here regularly, and I can't hear the train whistles where I live during the day, even though I know they still toot them, but at night I can here the trains that have got to be at least ten miles from here. Why is that?
I would be curious if the sound of these kinds of trains carried in the same way. Normal train whistles aren't really unpleasant, but I wouldn't want to be listening to screeching noises from several miles away while I was trying to sleep. (The fact that I usually sleep during the day is irrelevant. =P)
My Webcomic: Asylum on 5th Street
Videos of maglev trains, with sound. My apologies in advance to the host.
/.'ing commence!
Let the
Sapere Aude - Homer
Of course, if it works too well it'll sound like someone's letting the air out of every tire in the block...
The sound of a regular train (been a while since I've heard one) is rythmic, higher pitch clicking. I would guess that the maglev might be more lower frequency. Also, one might wonder if there's a sound beyond the range of human awareness that might be contributing to the feeling that the maglevs are "louder" or more annoying.
I dunno ... you tend to feel louder high pitched sounds in your ears, whereas the lower ones you might feel more in your body.
The author of this post would like to point out that unlike other posts, this one was more stream of thought, and less composed than his previous ones. In other words, he's talking out of his ass.
I talk about stuff.
"Conventional" trains make noises ranging from low rumbles (slower trains) to what resembles gigantic versions of the "fwooooooooosh" of a racecar passing you (Acela and other modern high-speed trains). But loud, high-pitched sounds coming from a piece of machinery (e.g. a train) could make people think the machine is out of control.
;) ) and crush the hapless onlooker...
High-pitched mechanical sounds carry a connotation of machinery operating "out of control", or running faster than it should. I'll put it this way. If you walked into, say, a widget factory, and heard the machines cranking away with a low rumble, wouldn't you feel more comfortable than if they were generating a constant high-pitched whining? In which scenario would you fear, deep down in your gut, that one of those machines is about to go haywire, break down, and shoot a cog in your general direction? This is regardless of the actual speed of the machinery. Low sounds are just less unnerving in this case. (Or so I feel...)
Perhaps the sound of a maglev operating at 150mph would be more unnerving than that of an Acela train operating at 150mph since the nature of the maglev sounds would make it "sound like" it's more likely than the Acela to disrail (even though, as a maglev, it already is 'disrailed' in a sense
Honey, I shrunk the Cygwin
FTFB: The researcher postulated that unfamiliarity with the noise might be part of the problem.
OK, and it even got an insightful mod...
If by "obvious" you mean "stated at the end of the freaking Slashdot summary" -- yes, it's obvious.
This seems like an appropriate question....do I just not get the joke.
Some participants in the study said the sound made them 'feel insecure...
No wonder my self-esteem is so low!
Under capitalism man exploits man. Under communism it's the other way around.
We don't get the freigh train whistle in The Netherlands, that I'm aware of. So the first time a freight train passed by me here in the U.S., you bet it freaked me out.
Now... I'm used to it.
Remember how when trains were first introduced, cattle would freak out, and the farmers were pissed at the railroad companies ?
Nowadays, trains zip by cattle many times a day, and they don't even bother to look up anymore.
Yes - people would just have to get used to the sound.
Unfortunately, people are still afraid of change - even if it's just a change in the sound of a train.
Where once upon a time new technologies were just introduced, we now run the risk of getting them bludgeoned to death by special-interest groups and environmental impact statements. There is no reason why in time maglev sounds should not become a familiar part of the soundscape, barely noticed if at all, and a realisation that people might be uncomfortable with something just because it is new may help us determine whether something really is damaging or if it's just a baseless case of NIMBY (as opposed to "it really is damaging, so get it the fuck away from me") when people oppose something new.
(aplogies if this is incoherent... it's been three hours since my last coffee)
trains vs. trams :)
- NYC's Emeregency vehicles.
- Living next to a maternity ward.
"MagLev Trains Annoyingly Delayed"
Most of the articles I see about these (many of them here) are about how the projects are being cancelled, or there are problems that keep holding them back.
Like the noise issue. Current trains make a lot of noise... is this noise so bad that it outweighs the benefits of a MagLev?
Looks like we have to buy a cdrom to get decent picture and audio....
No it doesn't. It's legit. Continue the /.ing.
Sierra Tango Foxtrot Uniform
Anyone know why mag-lev's are noisy? I was one of the people that thought that these trains would be quiet Apparently they don't record the sound when they show these trains on Discovery Channel or PBS because they're always whisper quiet in the documentaries. . . .
Many years ago I had a girlfriend who found the clickety-clack vibration of a train, well, exciting if you know what I mean. One of her fantasies was to spend a night in a sleeper car. Unfortunately the opportunity never came up, at least not with me (:
That is something you'll always have with new technology.
At first the 'look and feel' of windows scared the hell out of me. While now it still does. Oh, wrong example.
Other ecample. At first ringtones used to annoy but now it just irritates me. Oh, wrong example again.
Privacy is terrorism.
I vote that they attach large speakers all over the maglev trains, and play the tie fighter sound while they are going really fast. That'll teach 'em to complain about the noise!!
http://slashdot.org/article.pl?sid=02/07/31/161425 0
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
I wonder if it's perhaps as simple as our built-in responses to shrill sounds.
Primates tend to make more shrill prolonged sounds when in distress. We are likely hard wired to go on alert when we hear distressed sounds from another primate. That would explain uneasy feelings and rating the sound as more intrusive and objectionable than a rumble and clicking sound which would be fairly meaningless to the lower parts of the brain.
It's a two fold problem that will likely call for psychologists and neurologists to determine what is so distressing and annoying about the sound, and then accoustic engineers to figure out how to alter the sound so that it no longer has that characteristic.
Nothing more than a hypothesis here, but quite testable.
Edison marched men with lightbulbs on their heads through a parade in New York . . . this scared the willy's out of many people because they associated light with fire and thought that these mens' heads were on fire . . .
As new technology becomes familiar, these things become less disturbing and finally commonplace. I assume that the same would happen with sound from mag-lev's . . .
The annoying sound is the one those people with pacemakers make as the train gets going.
the major advances in civilization are processes which all but wreck the societies in which they occur - A.N. White
The article was very skimpy on the details. Where were these tests done. How many people were tested. What kind of noise was it? There is noise pollution everywhere now-a-days. So, even if this comes as a surprise, trains are a great means of transportation, and seeing that the maglev is fast, there have to be more tests done before anything is concluded.
The duration of a train traveling at 60 mph is more annoying than a Maglev train of equal length travling 250 mph, simply because you have to put up with it longer.
Sure the sound is annoying, but if it is gone in 15 seconds as opposed to 1 minute, I think people would get used to it.
Sierra Tango Foxtrot Uniform
Who woulda thunk that we could sleep through traffic noise, normal rail noise, low-flying jet aircraft etc?
a friend of mine had an apartment in Chicago where the trains ran 8 feet from his window. every 7 minutes you have a train running by.
he said it did not bother him... I about lost my mind staying there one weekend. with the window open in summer you cannot yell loud enough to be heard over the passing train.
Do not look at laser with remaining good eye.
this test was actually done the old fashioned, wild-west style.
Test subject puts ear on rail road track, hears train, moves of track.
Test subject puts ear on maglev track, no vibration, doesn't move off track in time - no wonder they freak out!
Guy That Sits One Cube Over ... Annoyingly Loud
... but subscribers can read it now by stopping by my office.
My Slashdot submission about this will be enroute to the Slashdot rejected bin in a few minutes
<sarcasm>
Wonderful approach! Ignore it and maybe the problem will go away. Why would you actually want to try to eliminate the source of the noise?
</sarcasm>
The web in some high speed paper mills moves at 8000 fpm, or about 90 mph. It's a 400 inch wide piece of nylon webbing, on top of which a warm slurry of .5% paper is sprayed at high pressure. It goes over rollers and dewatering points, where the water is sucked out of it by vacuum. Some of the rollers are small, so they have higher RPMs. At the other end of the machine, there are huge heated drums spinning at a faster rate (to pull the paper out). All of this is accompanied by pump noise, air compression noise, and vibration. It is so loud that earplugs are mandatory, and your chest hurts from merely being in the plant.
But I know exactly what its doing, so its not "out of control".
I want to delete my account but Slashdot doesn't allow it.
Looking at some of the pictures of Maglev Trains, the track resembled a concreet trough, rather than the conventional flat rail/roadway track. This would cause the air (and sound) movements to be altered and possibly create a different sound
the turbo trains of the late 1960s were jet-powered, and also annoyingly loud. Were canned for that same reason.
If they polled people living in a city with a lot of commuter trains, then these people might rate the mag-lev more annoying than the conventional trains that they are already accustomed to.
If they polled people living in an area without any trains and the people weren't used to conventional train sounds, perhaps they would rate the sounds of mag-lev's and conventional trains equally annoying or more close to equally annoying than the previous group.
Characterizing the difference between these two group may help identify how much of the results of this poll are due to people not liking the idea or sound of any trains near them and how much of the dislike is specifically due to the sound of mag-lev trains.
Additionally, I think that the results would be significantly different for those that may live in cities that would benefit from mag-lev's and those that live in small towns that high speed mag-levs may pass through without stopping (One may have a more negative opinion about the sound of a mag-lev if the sound does not have any associated benefit for the individual)
Perhaps the most impartial group to sample would be a group in a city with no trains and no plans to get a mag-lev in the future . . . but then who really cares about these people anyway (with respect to the sound of a mag-lev that they will never have to deal with on a regular basis)?
Unfortunately this article, like so many others, draws conclusions from the data without giving the reader enough information to draw his or her own conclusions or even agree or disagree with the author.
.. but tapes of the sounds produced by magnetically levitated and normal trains
Maybe they shouldn't have used magnetic tape around gigantic magnets.
For a guess - big fast moving train causing atmospheric displacement resulting in vibrations and thus sound. Add to that inter-car vibration, maybe some hum (and harmonics) from the power supplies on the rails, and the fact that the trains are not perfectly smooth, but have ripples in their skins (windows, door openings, vent stacks, etc.)
What I didn't see in TFA was a mention of how fast the maglev was going in comparison to a regular train.
-T
You're so right. For example, I have a new technique for extracting gold -- GOLD, I tells ya! -- from common sewage. It involves simply blasting a stream of "quicksilver" through the municipal sewer once a night. The quicksilver bonds with the fluxion and good humors in gold that's suspended in the water as a result of toothbrushes rubbing it free from people's fillings. That scraping, rushing noise may be excruciating for you at first, but you'll adjust.
What, you mean I should have to prove that it works and that you're not going to die of mercury poisoning as a result of my new process? C'mon... once upon a time, I could just have introduced it without all these environmental "special interests" getting in the way. What kind of a world do we live in?? You're stifling my innovation. And here I was going to generously offer to sponsor a public park for your kids with my earnings.
Seriously, don't you think there's a balance to be struck here? Doesn't seem to me like asking the question "Maglev trains are perceived as having a more disturbing sound -- Why?" is a sign that ingenuity is dead. Personally I like living in a world where airports need to think about the noise produced by their traffic patterns. If we figure out what quality these trains might have that makes their sounds more irritating, we can decide whether to do something about it and how much it'd cost. No harm done.
"Fundamentalism" isn't about divine morality. It's about human authority.
Even though they don't have wheels, they still require large engines for power generation. So right there you've got most of the same noise a traditional train makes.
The rest of the noise is likely from the high voltages and speeds involved. Ever hear a transformer buzz? Or an old flourecent light fixture? Same idea really. The eerie buzzing noises are probably what freak people out.
=Smidge=
I figure that most of the sounds that you cite are probably somewhat similar to the sounds of a conventional train . . . with the exceptions of power supply hum and perhaps the pitch as a function of speed . . . which leads me to exactly your same question . . . how fast was the mag-lev going with respect to the conventional train?
the guy instead of actually asking people who live near a maglev/ordinary tracks what they thought
he played recordings and then asked subjects (presumably in his lab) which they disliked the most ?
anyone who lives near a train laine can attest comparing the real thing (and all its physical vibration) to one of a recording played through a 100w labs hifi is laughable, really. if he had about a 50k rig he might get close to the physical vibration and noise factor , ever notice anything is annoying if its not reproduced correctly ?
Then we ask what clips did he play ? a selection ? random ? how many in the collection ? distance away from the mic ? frequency captured ? (20-20 aint enough)
lots of questions but simply playing a recording and saying yes or know doesnt really constitute much of a study
Yeah, those tie fighters are so loud, they are even loud in the vacuum of space !!!
Im not here now... Im out KILLING pepperoni
Considering maglev trains sound very much like a low-flying A-10, it's not surprising that people find this sound 'disrupting' or 'uncomfortable'. I don't think it's a specific frequency/pitch issue; it's more of a "holy-crap-we're-under-attack" issue.
I understand your point, but at the same time I wonder if "resigned to" might be more appropriate than "comfortable with". Most of the time I never notice all the noise around me, but every now and then I stop and listen to the sound of the ventilation and the computers humming and the traffic outside and think how nice it would be to be able to just experience something like actual *silence* once in a while, and, for example, to not have to turn up my headphone volume to 11 to hear all the details in a classical recording with a lot of dynamic range[*].
If you stop to listen a moment (or if you think what it's like to be in a power-out), it's actually kind of shocking to realize the amount of noise we put up with on a regular basis.
--Bruce Fields
[*] It might make an interesting study, by the way, to look at the way music has evolved in relation to the ambient noise around us. Try listening to any modern pop album next time you're driving on the highway, and then try listening to a string quartet. The string quartet will be almost impossible to follow, but the pop songs will still make sense.
I have to say, I live in the city right next to an Acela track, and it's one of the most amazing things I've seen. The tracks in question have MBTA (commuter rail) trains, Acela express trains, and T (above-ground) subway cars pass by on a regular basis.
The loudest and most annoying are the dilapidated orange line subway cars, which are very old and make a lot of clicks and clacks and screeches. The commuter rail is definitely louder, but it is uch more pleasant - a bassy rumbling, depending ont he speed, maybe more ominous if you don't know what it is. The Acela is QUIET in comparison - it seems as if the only thing you can hear (not true, of course, but comparatively) is the air being so violently pushed around as it whooshes by. And it's so quick (when not even at full speed in the city) that it's almost tantalizing, making you wish you could see it for a little longer. It's almost like an arrow shot from a bow, it sneaks up on you as you can't hear the rumbling as it approaches, and then it's gone by so fast you're almost not sure if you really heard it in the first place.
people used to run screaming at the sound of a motorcar too.
in this age of communication i'm just not getting through
You'd be surprised how much you develop a "pavalov's" type reaction to the sounds around you. I know from being a tech on machinery that you can often "hear" a machine problem from subtle changes if it's even slightly out of calibration... People are tuned to react a certian way near trains/ hearing trains... it spooks them.
Three years ago, I went went on a guided tour to Papenburg/Germany and had the chance to experience the Maglev for about 20 minutes. First of all: don't believe what critics say. Try it yourself - if you get the chance to ;)
The Maglev is definitely NOT loud, nor does the sound make you feel uneasy (you could barely hear a train passing at 100mph, and a full-speed maglev was not at all annoying either!). Plus, there are no vibrations - a little different from conventional high-speed trains.
The top speed was 430kph (almost 270mph, on tracks initially developed for a maximum speed of 100mph - the tour guide claimed).
just my 2 cents
as in the sound they make is used to instill fear and such. There are some real interesting uses of noise.
:)
Of course what helicopters sound like in movies is usually different than in real life. Friends of mine can tell you what chopper is coming just by the sound from the blades.
That being said, instead of masking the sound of the train perhaps they can tune it to sound more pleasant
* Winners compare their achievements to their goals, losers compare theirs to that of others.
is a maglev train?
Going from South Dakota, to Indiana, to Arkansas
eeeeeeeeeeeeeeeeeeeeeeeeaaaaaaaaaaaaaaaaaaaaaahhhh hhhhhhhhhhhhhhheeeeeeeeeeeeeeeeeeaaaaaaaaaa
I thought they had permanent magnets on the trains, and that it was electromagnets in the rails that are powered and provide the propulsion and control the lift. Thus requiring only modest on-board power for lights, heat/AC, control equipment, communications equipment, etc.
Is this not correct?
You can grab some more clips here (scroll down to the Ground-Borne Vibration Characteristics of Acela and TransRapid TR08 Maglev presentation about halfway down).
Sorry, no sound, my Olympus C2040 only does video.
(note that I'm the author of presentation and I took the videos, but I don't work at that company anymore).
.neat thanks
Anyone who lives in the Bay Area and is a Mr. Bungle fan recognize the similarity between the BART trains in the east bay and the sound of nitrogen bubbles a-popping in "The Bends"? It's easily the most painful song I've ever heard (and sadly missing from the iTunes store, or I'd provide a link).
I suspect that the "bends" sound at the end of the song is actually just a sample of the BART trains which has been digitally tweaked a bit. Seems like a somewhat telling relationship about the nerve-grating qualities of the sound of trains.
You drank my drink, you drunk!
Not exactly. Maglev's are driven by electricity (electro magnets), and the generators are placed at substations along the guideway. So there is no "generation" noise that you hear from the vehicle (although part of the noise you hear from the maglev is attributable to the switching noise of the magnets and stator spacing).
Now your 'transformer buzz' comment is relevant. As I said, the power is generated and distributed at power substations along the guideway. When the train is accelerating along the guideway, the substations have to crank up the power, and they get pretty loud.
a kid in Boston. The ear-splitting screeching noise it made in turns was horrible and scary, and the sparks sure didn't help. Now, living in Texas, I'm nostalgic for it. I assume it will be the same with mag-lev trains.
The rent on these places is about half of what it would be a couple of blocks from the tracks in the same neighborhood. This could have a lot to do with why he tolerates the trains. I can see how people deal with a constant noise, like a waterfall. But when its intermittent like that, I have no idea how the body can learn to tune it out.
I think the reason why people might be annoyed by the sounds of a maglev passing by is the fact that at the type of speeds maglevs operate (350 km/h to 500 km/h), the noise is NOT caused by physical contact with the overhead wiring and the steel wheel/steel rail contact but the aerodynamic noise caused by the shape of the maglev train itself. This means they'll need to computational fluid dynamics research into reducing the noise footprint of a maglev train.
Indeed, this was a major issue with the upcoming Airbus A380 super-jumbo airliner; they had to go to single-piece moving surfaces on the wings instead of louver-type moving surfaces found on the Boeing 747 because the louver-type moving surfaces generated quite a lot of aerodynamic noise above 320 km/h flight speeds.
(Pulse Width Modulation, PWM) of the power to the electromagnets. That frequency can be changed, within limits. I've been on mag-levs at Kings Island (Ohio) years ago, they are a bit annoying.
Insanity: doing the same thing over and over again and expecting different results. Albert Einstein
During the day, air near the ground starts off cool.
At night, the warm surface heats the air above it.
This will affect density. Variable density will
cause sound to bend one way or the other.
The main noise component of the maglev trains is aerodynamic noise, just as you would have from a plane. This pretty much explains the comments about the similarity of the noises... And such noise can not really be cancelled; it might be possible to shield it a bit, but it will be there, and it can barely be directed. There might also be some electrically induced noise. However that noise will be easily covered by the aerodynamic noise. The noise with conventional trains is a mix between rolling noise (steel on steel, depending a lot on the roughness of the wheel surface), and the aerodynamic noise. This mix is of course also creating a totally different spectrum. Overall, this study looks to me quite a bit like a "publish or perish" study... not much substance, not really well worked out (playing sounds in a lab environment does not really have much to do with "real world" annoyment...
I can take a good deal of rumbling, but no amount of exposure to high pitched whines and such has desensitized me to them.
Noise of any type is a result of some inefficiency somewhere. Be it the air displacement from poorly developed skins and attachments or transforming the electricity with inexpensive components. I'm sure they can isolate the offending noise and design it out of the equation. Still did not get a good answer on here as to what exactly was causing the noise. Although there is some good speculation.
Once I'd seen what they were capable of (you'll have to imagine a hundred 20mm rounds per second hitting a soldier; I'm intentionally not seeking a link), that sound took on a whole new meaning.
There's a whole ethical debate on this sort of imagery: can national security be weakened by US citizens being repulsed by the carnage our weaponry is capable of? Imagery impacted US public perceptions of the war in Viet Nam, and we've advanced a lot technologically since then.
I realize I'm off topic by here, but whining about maglev (pun intended) seems silly in comparison. As with jets and computer fans and traffic noise, maglev's purpose is considerably more benign. We can work around or get used to the sound.
It's the noise of all my pots and pans flying across the room into the wall nearest the train when it goes by!
the noise neighbours hear is very different.
It's from a different angle, it's not damped the same way,
and it had the Doppler effect to take into account.
It's in no way comparable.
The frequency content of a sound has a lot to do with how comforting or annoying a sound is. Incredible ammounts of money have been spent on this in the auto industry alone. Studies are done on the sounds of a car door closing to find the sound that makes people feel the most secure when the door has closed. What they've found is that the sounds of car doors closing with more energy in the low end of the frequency spectrum makes people feel more secure in the sound of a door closing.
Now lets apply this to trains. Normal freight trains generally produce a lot of low frequency sounds. Generally around 300Hz and below. Now the maglev trains could be a lot quieter, but if they make higher frequency sounds, even at lower dB levels, the sound will seem a lot more annoying than freight trains.
I lived next to a railroad for 8 years as a kid, like 50' from the railroad. in fact, except for a few occasions, I mostly never heard the nightly 11pm train go by.
Then again, I'm a guy would could fall asleep on a jet engine running at full throttle.
Yeah, this coule be a little off topic, but it really does seem like the obvious solution to the mass transit problem to me. It was incredibly quiet when I took a ride in the prototype. I've never heard a MagLev though.
SkyWeb Express Personal Rapid Transit:
http://skywebexpress.com/
I live in an apartment building that's fairly close to some railroad tracks. I haven't gotten used to it actually. I notice when a train is going by every time. I especially notice when they make LOUD SHRILL GRINDING NOISES. It's the most annoying noise I have ever heard. I have no idea what's making that noise, but how could a maglev be any worse? If my window is open it drowns out anything quiter than normal conversation. It is LOUD, and you would think there would be some kind of government regulation about the train tracks and a residential building being so close together.
I imagine it's even worse for the people in the apartment building that's between me and the tracks.
I'm thinking 100 years ago the sound of a steam engine freaked out the locals, their farm animals, etc. I think that the speculation about "it's just unfamiliar" is probably dead on.
To the best of my knowledge, there are three sets of magnets involved in real-life Maglevs: Levitation, Guidance, and Propulsion. All three need realtime computer control to keep the train floating within inches of the track and to keep it moving smoothly. In all of the real working systems I've read about, electromagnets on both the track and train are used to accomplish this.
I believe there are some systems however that use inductive principles to provide most of the lifting force - using wheels until the train is up to speed and the car can levitate properly. This cuts down on the amount of on-board power required, but a good deal is still required for the other systems.
I've never heard of a real train using permanent magnets. Only desktop models. I can easily see how cost, since cost per gauss - no rhyme intended - is much less for electromagnets than permanent ones when you get into really powerful fields. Safety is also an issue, since a service tech will probably have to take a wrench to the thing sooner or later, and that can cause a few lost fingers...
So all told the train will definitely require on-board power generation. I honestly can't tell you if it would be more or less than a regular train, but it would probably be over 200kw easily. (For reference, a normal commuter train powerplant is around the megawatt rage and up)
=Smidge=
You're right, they're techinically very quite once they picked up speed. Unfortunately, maglev trains move by alternating magnetic field at a high rate (low oscilation, slower speed, higher oscilation, higher speed). So there will be some times when the oscilation move into perceivable range (20000 hertz) at which we will heard a high pitch screeching.
In US, you can easily buy enough major firearms to wipe out your neighbourhood but a few little fireworks are banned.
The maglev goes faster and when it does it pushes more air than a regular train.The power to move the train increases with the square of the velocity due to air friction. That power is what bystanders are hearing. I couldn't read the study but I'd be curious to see how people rated two trains moving at the same speed.
In any event, if maglev is ever going to prevail, noise is going to have to be dealt with. It can be done either by encasing the train in a tube to isolate the noise or better yet, encase the train in vacuum tube and then really crank up the speed since you're not shoving air out of the way. The inventors of superconducting maglev which uses repulsion instead of attraction like Transrapid figure that a train could go coast to coast in under an hour using the equivalent of about 20 gallons of gas. The cost of course is in building and evacuating a 2000 mile long tunnel.
I wonder if the noises are considered more annoying just because they are less familiar. With standard train sounds, you KNOW what it is, and you know you don't have to deal with it. You are already used to filtering it out.
Nobody is that used to a maglev train sound yet.
Yes, No, Maybe?
plus-good, double-plus-good
The sound a Maglev train makes may be considered "disturbing" by humans for the same reasons that the sound of nails-scratching-on-a-blackboard is.
Thank you, Cecil.
---anactofgod---
---anactofgod---
"Equal opportunity swindling - *that* is the true test of a sustainable democracy."
Firstly, european maglevs suck. The japanese ones are far better designed when it comes to noise. Just look at the pictures of these things. The gradients in the front and the back are at most 2 meters long, while the japanese ones are sometimes as long as 20 meters.
And a solution for the future might be to put the trains in tunnels without air. The topspeed will be immense, and no noise will ever be generated.
So, you get:
further broken up as:
And here's some really odd ones:
So, that's decibels. 1 Bel, incidentally, is 10 decibels, so just devide by 10 (or 20 for power). However, since you then end up with lots of decimals, it's usually not so useful.
-T
sounds much like what an ugly Wraith might sound like. The high pitched shrill contains hints of human screams that eminate from unknown directions. People in the vehicle feel uncomfortable.
Whereas a freight train sounds like lifeless metal. Annoying but familiar.
Maybe we should compare this to when steam trains were first largely used, in both industry and personal travel. We've all heard the stories from older members of our families, or read them in articles, of how fearful people were of the noise that the steam engines made. This is a natural reaction to something new and unknown, and in time can be overcome. But that's not to say that research shouldn't be carried out into the acoustics of the thing, just let's not bouycott the trains just because they're big and loud and scary.
They bitch now...
Wait until these things go supersonic.
THEN they can bitch about the noise.
Or more likely they'll have that annoying noise problem dealt with by then.
One, the ambient noise floor is typically 20+dB lower at night when all the traffic stops; that makes a huge differnce to the ability to hear things in the distance.
;-)
Two, and more significant in the effect you describe, is the fact that radiative heat loss by the ground to the night sky cools the air near the ground. Sound which otherwise would dissipate upwards can then be diffracted back towards the earth, because effectively it is radiating in a medium which has a varying refractive index - think how graded optical fibre works
I read somewhere recently that there is a news blackout at Dover Air Force base, because that's where all the coffins come back from Iraq, full of the bodies of American soldiers killed since we "won" the war.
Request your free CD of my piano music.
We humans carry a ton of hard wired behavioral baggage from the times when our ancestors spent the better part of their days in the trees.
You can tell if somebody is watching you, by yawning, waiting a moment, then looking at them. If they're yawning too, you just caught them being sneaky. That's a primate thing. Smiling... the showing of teeth as a stress reducer, is way primate... look at chimps and baboons.
That feeling you get when a person uses chalk wrong on a chalkboard? That's a hold over from the time we all screeched a warning at one another. We have a deep sympathetic response to high pitched screeching sounds, they alarm us, make our hackles rise, give us the heebie jeebies. It make sense, it was the defining behavior that determined which of our ancestors procreated and which ended up decorating panther poop. In a recent article, there was a conversation about antisound being used to cancel unpleasant noise. I wonder if this is an area that might benefit from that technology?
Genda
Damnit, I wasn't trolling. I was responding to the trolling parent! You must be from West Palm Beach, moderator.
I metamoded the Troll moderation of your AC reply to this comment "Unfair" - you weren't trolling. Eliminating unfair moderators one metamod at a time.
An Indian-American Hindu committed to non-violent thought/speech/action alarmed by the global explosion of radical Islam