Environmental Noise Characteristics Test for Tram Running in Small Radius Curved Section

Objective Due to complex wheel-rail relationships, trams are prone to generating severe whistling noise when running on small radius curved sections of urban roads. Therefore, it is necessary to study the environmental noise characteristics for trams and the noise reduction effect of rail oiling lubrication. Method A typical small radius curved section of a domestic tram line is selected for the environmental noise field test. The A-weighted sound level characteristics, frequency characteristics of rail noise before and after rail oiling, as well as the noise reduction effect of rail oiling are compared and analyzed. Result ＆ Conclusion When trams pass through small radius curves, the whistling noise causes a sharp increase of the A-weighted sound level by 5～12 dB（A）, and the noise on the curve inner side is 3～10 dB（A） higher than that on the outer side. The main frequencies of the whistling noise are 1 051 Hz and 2 280 Hz（the latter is more significant）. After oiling, only some trains experience whistling, and the 2 280 Hz peak is significantly reduced. In one oiling cycle, the equivalent sound level mean value is reduced by 2.4～3.9 dB（A）, and the maximum sound level mean value is reduced by 5.7～7.7 dB（A）. Increasing the oiling frequency can further reduce the whistling and the sound level. The noise reduction effect of rail oiling is significant, and in practical applications, it is necessary to balance the noise reduction effect with material cost for oiling frequency optimization.