One of the most admirable sounds in the right sort of place is that of a train: its rumble and whistle. The "right sort of place" is likely to be an isolated rural or backwoods area. From my blissfully lonely camp I hear a busy train track that parallels the Old Lincoln Highway, which was built over the Oregon/California Trail, as it hooks around a small mountain range. If you can actually see the train, its aura and mystique erode.
A modern road just blasts right through the mountains. Such is the power of the diesel engine, caterpillar treads, and Blaise Pascal's hydraulics. Old routes follow the contours of the land instead of trying to annihilate them. I learned just yesterday how rugged this small range of mountains was, as I mountain biked through them.
It has been several years since the sounds of trains have affected me so much. How do you explain the mood that overtakes the hearer of train rumbles and whistles? A look at the Merriam-Webster's might give a clue.
WISTFUL, adjective, 1: full of yearning or desire tinged with melancholy.
That word is so perfect for this situation, but "yearning" for what? And why "melancholy"? Perhaps the sound of the unseen train remind the hearer that 'no man is an island'. There is a big busy world out there, away from his own little paradise. And he likes being reminded of it, and connected to it, although in a safely indirect way. This works for the world of our not-so-distant fore-bearers, as well.