Annoyance of interior noise in high-speed trains: Determining acceptability thresholds for different passenger activities.

One of the main advantages of railway transportation is that it allows passengers to engage in a variety of activities. Thus, train operators and manufacturers seek to guarantee that the train background noise does not prevent passengers from conducting these activities. The goal of this work was to investigate the effects of background noise on passengers' perception and activities and to determine thresholds of acceptability for these activities. It combined two approaches. In the first experiment, participants rated short-term annoyance elicited by recordings of train interior noises on a continuous scale (psychoacoustic approach). The results of a multilinear regression analysis showed that loudness and emergent tonalities were the most important drivers of annoyance. In the second experiment, participants were seated in a mock-up of a high-speed train and performed tasks common to first- and second-class railway passengers (watching a TV series and reading a text), with different background noises (cognitive activities approach). Interestingly, the results showed that in the second approach (i.e., when their attention was drawn away from the sounds), only the loudness had an impact. Overall, combining these two approaches yielded an analysis of the factors driving annoyance and a definition of thresholds for different on-board activities.