How comes that, when the wind comes from the railway, I can hear the trains much better. I understand that it should reduce the effective distance of the railway, but the wind is usually not over 50 km/h, very small compared to the speed of sound (1200 km/h), so the effect should be tiny.

When I utter a phrase, that phrase will be sound waves moving away from me at the speed of sound. If I were able to suddenly propel myself (or a microphone) forward at twice the speed of sound, I imagine that I would overtake the sound waves I generated earlier at the speed of sound, and as a result I would hear the phrase I uttered in reverse. Some people I have discussed this with find that strange or hard to believe. Is my view correct?