h a l f b a k e r yRecalculations place it at 0.4999.
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We know how loud trains are, right? Where I live, freight trains regularly pass on a track 1.5 to 2 miles (2.5 to 3 km) away, but they can easily be heard clearly (not just the horn, the engine itself), even though we live in a fairly foresty place. That can't be a good thing.
The question is how
to quiet them. There are a couple of solutions. Mufflers, loudspeakers that propagate sound waves 180 degrees out of phase, actual sound insulation in the engine room would all work, with varying degrees of effectiveness. Out of the three, I believe the first two to be the most likely to work, although it would be a hard thing indeed to find loud enough speakers to have any real effect. There are other ways, I'm sure.
go to the source
http://www.gmemd.co...ght/sd70m/index.htm
[ato_de, Oct 04 2004, last modified Oct 05 2004]
[link]
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You must have been hearing nice trains. The trains where I live are nasty. An ugly horn (meant to scare the living daylights out of all things on or near the tracks), and the clunk is a massive rumble not unlike a tornado, but the worst part is the loud, unmuffled (so far as I know) engines themselves (often three or more pull trains here). Not nice here. |
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I like train whistles too, by the way. Steam engine sounds, too. |
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Quite so, although I'm not sure the rumble is the *majority* of the noise. But I won't argue the point. What I'm after here is to quiet the engines themselves. They are, after all, at least a significant noise contributor, and the easiest to quiet. The engine noise bothers me more than the rumble, anyway. |
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i don't think active noise
cancellation works from the noisy
end very well. that is... noise
cancellation headphones work by
analyzing the waves coming at the
ear, therebyb automatically taking
into account any local
resonance, reflections or variations
that the sound waves may be
subject to on the way form the
source to your ear. |
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by creating the "anti-noise" at the
source, you cannot necessarily
account for all the variations that
might occur once the sound has
travelled away from the engine. |
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not to mention that trying to
determine the directionality of
each source of sound form an
engine and mounting a speaker so
as to offer the exact same
directionality would be a bit
tricky... |
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no, i say engine insulation is the
way to go. unfortunately, the only
really good way to muffle low
frequency sounds is by taking up a
lot of space with a lot of heavy
material. nothing beat two
cinderblock walls with a foot of
dead air between them. by adding
all this weight to the locomotive,
you'd probably need to up the
power of the engine, thus upping
the noise... |
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Uh, yeah. What about something in a good muffler (is there a different word fer that in the UK?)? |
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<Flashback - Cheap Motel Room - 1968 - 3:30 a.m./>
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#######(!!!!!!~ !!!!!!~ !!!!!!~ !!!!!!~ !!!!!¶(o)########
_________________________
__________
: o
: o
¯¯¯¯¯¯¯¯¯¯
__________
: o
: o
¯¯¯¯¯¯¯¯¯¯
</Flashback - Cheap Motel Room - 1968 - 3:30 a.m.> |
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trouble with a muffler (like on a
car) is that the muffler only
muffles the sound that would
otherwise be emitted from the
tailpipe of the car. an engine is
making a whole bunch of
explosions all the time and that
sound is traveling along the same
path as the exhaust. |
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the diesel engine on a train is
making a great deal of noise
besides the noise that comes out
the exhaust vents which are, i
assure you, already muffled. |
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That's very good ASCII art,
[thumbwax] -
beautiful.
I quite like
freight trains, especially the
mile-long ones you have in the
US.
[galukalock] - isn't the
problem really that the freight
trains near you make the wrong
sorts of noises? It's going to be
much cheaper to fit the trains with
old fashioned whistles and change
the clunky noises to slightly
different clunky noises than it will
be to silence them. |
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The idea isn't to silence them per se, just make them quieter. As I said earlier, the best way to go about it would probably be to use some kind of muffler on the exhaust. |
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[urbanmatador] Nothing personal, but I don't believe you. Gimme a link that says they already have mufflers. |
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There isn't a universal true answer. Train exhaust systems vary greatly with those intended for switchyard use requiring both exhaust and intake muffling, others that are turbocharged having no mufflers, but nearly all having some sort of exhaust spark arrestor system. |
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Okay, now we knowing that some are to having some kinds of a muffler, but for surely just in Russka. Some of a company in American United Statehoods is making mufflers for American Diesel Engines, but none showing if those engines for fact use the mufflers. What is certainly is, the mufflers could to be making improved in design, in cause for better noises absorbing. |
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Freight planes. That's right, 50 planes attached at the ends, flying through the air. Quieter. Faster. Making the world a better place. |
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How in heck can there the 4 fishbones to one croissant? |
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I once bought a home sorta near some tracks. In all the times I visited there was not a single train. |
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Then the first night we moved in, at 2 am there was a great thundering and the house shook as a beast of a train thundered through. Seems the track only functioned at night. |
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Lay the track in such a way that when passing a residential area, the train runs up and over a parabolic "hill" of such shape that at the right speed, the train is nearly weightless (not totally though, otherwise it would leave the track) - this should reduce the rumble factor a bit. |
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//by adding all this weight to the locomotive, you'd probably need to up the power of the engine, thus upping the noise...// |
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Locomotives need to be heavy. While I don't know if they have added ballast, they are hardly designed to minimize weight. Removing some weight and adding sound dampening would not be unreasonable. |
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That being said, I think the reason this idea is getting fishboned is that the author is basically saying "I hate loud trains and think it should be possible to quiet them" without offering any particular original insight as to how that should be achieved. |
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Well, I did try to. I mentioned sound cancellation, dampening, and mufflers (or better mufflers if they already have them). It seems hardly anyone paid attention to that part. |
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//Well, I did try to. I mentioned sound cancellation, dampening, and mufflers (or better mufflers if they already have them). // |
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Do you seriously think that the companies who build locomotives haven't already thought of such things? |
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If you were to suggest something a bit different, such as having the locomotive contain a large bank of batteries which would be charged when the train is in the middle of nowhere, and which could power the locomotive when it's in a residential area, that might be less likely to get fishboned. Not because it would necessarily be practical (batteries aren't terribly efficient) but because it would mark something which AFAIK railroads haven't tried to do. |
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What's in it for the railroad companies? |
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Ditto. Just the engine noise, please. |
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[cat] Quite so. I mentioned those particular methods as examples, not strict laws. There are a number of ways this could be accomplished feasibly. |
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[wax] If the railroads weren't as noisy, land values in the area would quite probably rise, if only a little. Multiply that little bit ($100 per acre, say) times all the residential zones near railroads (500,000 acres, to be conservative), and that's a substantial increase in taxes, even with the small numbers here. I'm sure some kind of deal could be struck with the government. If not, laws could always be made. Similar laws are already in effect for cars. That's one reason they have mufflers. |
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//Usually, it's a wheel or two out of alignment// |
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I thought it was a flat spot on the wheel. No matter. They still sound terrible. |
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