Hey everyone!Today my research is based on the main railway disturbance.These are:
- Noise vibration
First, my research will be on noise vibration .Then others will be on my next research.
Railway noise pollution can be either from airborne sound or from vibration-induced as a result of rail traffic . The main source of railway noise comes from freight wagons, followed by high-speed trains and inner-urban railways. However, locomotives passing and accelerating, freight wagons braking, vibrations from rail corrugation, and out-of-round wheels or vehicle coupling in shunting yards, are other sources of noise .
Noise levels vary, depending on the landscape and weather; open and flat areas allow noise to travel further than forest or mountains areas. In mountainous areas, the effect of noise is greater within valleys, when their width is less than the height of their walls, reducing the attenuating effect of noise . Frost can make the ground hard and impede sound absorption,but fog prevents noise from dissipating.
Noise above 55 dB(A), where dB(A) is a measure that attempts to correct the way the human ear perceives loudness, is considered noise pollution for humans, and the sound values in the range 65–75 dB(A) cause stress to the body, leading to arterial hypertension (high blood pressure), cardiovascular disease, and heart attacks . In Canada, the sound level of a passing train reaches values up to 85 dB(A), but between trains the sound levels drop to 43–53 dB(A) .Measurement campaigns on high speed trains in several European countries over 10 years revealed sound values ranging from 85.5 to 97 dB(A) when the train speed was between 250 and 350 k. In Japan Matsumoto , compared the noise as a function of distance and observed a high noise level of 64 dB at 200 m from a railway in the countryside, a value similar to that near residential areas (65.7 dB). In fact, in Japan, noise can still reach 72 dB at 50 m from the track, i.e., higher than the Japanese permissible standards of 70 dB A.