I have a playlist of "classical mix" for studying and Different Trains came on. I had to turn it off. I've listened to Steve Reich's piece many dozens of times and contemplated the source of the sound samples. I've wondered if you can hear any difference in the whistles. But a voice whispered in my ear. "It's not trains this time, is it?" Sprawling warehouses. Is that a data center or is it a camp? Either way, out of sight and out of mind. https://en.wikipedia.org/wiki/Different_Trains