噪声是一种使人烦噪,讨厌的声音。由于声波是球面状向外传播,流动型噪声源对环境的影响范围比靜止源更大;而且流动型噪声常是间断性的、使人更讨厌。铁路流动型噪声源种类很多,一般可分为机车车辆和养路机械两类。前者为组合的列车,体积长大,为线型噪声源。声波在列车两边呈圓柱状向外 Noise is a nuisance annoying noise. Because the sound waves are spherically propagating outwards, the impact of a mobile-type noise source on the environment is greater than that of a stationary source; and the flow-type noise is often intermittent and annoying. There are many types of railroad noise sources, which can be divided into two types: locomotives and road maintenance machinery. The former is a combination of the train, growing up, as a linear noise source. Acoustic waves on both sides of the train cylindrical outward