Lwiva
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- Apr 17, 2015
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Atafutwe janerose haraka !!! Asome kile mchina kaitusi Kenya kwenye hayo maandiko " yameandikwa the " great monkey hole"
Cost comparison SGR Kenya vs SGR Tanzania
Cost comparison SGR Kenya vs SGR Tanzania
- Thread starter Geza Ulole
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Lusematic
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- Feb 2, 2017
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[emoji23][emoji23][emoji23]
Phase 1 does not have noise barriers, its only in Nairobi national park as part of phase 2A.
Environmental considerations in phase 1 were high bridges in parks.
Geza Ulole
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how about noise barrier at the bridge across Tsavo national park? what makes the animals of Tsavo park any different from ones in Nairobi NP? don't they need protection from noise too?
Chamoto
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- Dec 7, 2007
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You guys are worrying about audible frequencies (20 Hz to 20KHz) how about those that are out of that range?
This reminds me of days we used to design circuits to produce high frequency signals (over 20KHz) to repelled mosquitoes, it was a project against malaria. Just because you have sound barriers humans can't hear, it doesn't mean some animals wouldn't be able to hear (noise).
Lusematic
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sijui izo suti zake nani huwa anamshonea....[emoji3][emoji3]
thisdayes
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Itakua fundi maiko
Kafrican
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- Jan 26, 2015
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Phase 2A has not been launched!
Kafrican
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- Jan 26, 2015
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Does rail ever produce inaudible frequencies??? Answer that first
Geza Ulole
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yes especially if the track is not continuos welded! and if the engine is diesel! that's a stupid question though!
Chamoto
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Physics 101 - wave propagation.
Any oscillating object (guitar, drums, piano,vocal cords, heart, diesel engine etc) produces some form of frequency.
Depending of how fast it vibrates, it can produce audible or inaudible sound. So to answer your question about rail, yes! They do make sound as the wheels pressing on them, some of the sound is audible and some not.
Travo animal population is sparsely distributed and its big, the largest park in Kenya. So adding noise barriers for few elephants will be too expensive in a cost benefit analysis
Kafrican
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Do you even know what inaudible frequency is? Its when something vibrates too fast to a point the clik klak is just one contentious high pitched line on a frequency scale ... why am I even bothering to explain this to a person who thinks diesel engine or jointed rail can produce such noise!
Kafrican
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Don't tell me about physics, or the possibility of rail producing inaudible high frequencies , show me evidence of rail producing that frequency level in terms of recorded frequency range (kHz) of train vibrations/sounds and also whats their attenuation distance (How far it propagates before its distorted)
Here is an example of how you can make that argument, here are the various noise levels of different objects in terms of decibels, For the sound to be inaudible to humans,, as you can see, a freight train is about 80db which is the same as a trailer truck.
Now since you know physics, tell me at what part or what moment does a train produce sound frequencies above 20,000 Hertz (Which is the limit after which humans dont hear anymore). The only time I can think of is if was a really fast train that had to suddenly deploy all emergency breaks. other than that,
Here is a comparison of different noise levels of either rolling of the train on the track, aerodynamic noise, engine noise, at different speeds... As you can see, only trains that go beyond 400km/hr are capable of producing over 120db that goes beyond 20kHz
