Experimental research of sound of trains at level areas

The paper presents the results of experimental studies of noise of trains on a flat site. The analysis of dependencies to reduce the external noise of trains, depending on distance, speed and type of train. The experimental results showed that the reduction of noise with distance is determined by the geo-metric extension of the front sound waves, sound absorption, increasing the sequence on a flat surface, the molecular attenuation of sound in air (at large distances and at high frequencies). The processes of noise reduction with distance does not depend on the speed of trains. The nature of noise depends on the type of train (decrease due to the geometric expansion depends on the length of an train). Reducing the distance is the frequency-dependent manner (once-ence in frequencies up to 10 dB).