While watching the ATN switching their northernmost customer over near the Guntersville Depot, I noticed that it was getting close to the test time for Marshall County, AL, to test their sirens. As I didn't feel like trying to go for a close-up shot of one, I decided to record this ambience, which turned out pretty well, IMHO. Sounds like you can hear quite a few sirens winding up during the test! The sirens heard are all various Whelen Omnis.
At the end, you can also see that I zoomed in on the ATN's train, which was switching at the time.
Marshall County, AL, tests on the 1st Wednesday of every month at 10 AM, weather permitting.