Comparison of wheel/rail noise radiation on Japanese railways using the TWINS model and microphone array measurements

The railway noise from conventional narrow-gauge lines in Japan mainly consists of rolling noise. A better understanding of rolling noise is required to reduce the noise at the wayside. In the past, in order to quantify wheel/rail noise, theoretical models, such as TWINS, have been developed, and measurements have been carried out with microphone arrays. The TWINS model has been validated in terms of noise and vibration, and used to predict the rail and wheel contributions to the total noise. Results from microphone arrays often give more prominence to the wheel than these predictions. In this paper, the TWINS model is applied to Japanese railways. Through comparisons of predictions with measurements for four types of wheel and one track type, it is shown that the TWINS model gives reliable predictions. Simulations are presented to represent a microphone array. These show that, in the frequency region where waves propagate freely along the rail, the microphone array can significantly underestimate the rail contribution to the noise.