RJM, I grew up near Trains and that is one of my favourite sounds, which I now also enjoy as I live just 3 miles from where I grew up! It's a vortex that keeps sucking me back.
...and I love it! Kian, I also enjoyed the tall Pines when Elliot was a wee babe! You guys are killing me softly! ♥ (and it's been decided that a Golden is in my future!)
3. The early morning chirping of birds in the Spring, especially after a long silent winter, around 4:30 a.m.