My sister has a vexing problem. She tells me that the gov't has made a rule that trains must blow their whistles two longs and a short for every crossing. She lives in Denver, and trains cross streets several times in her neighborhood. Several trains blowing 2.5 times over several crossings per night is disturbing her sleep something fierce.

We thought of earplugs and a white noise machine. Do white noise machines work? Do they have any downside? What does anybody know?

(I looked for ratings, couldn't find any.)