Why are locomotive horns mounted at the middle of the roof?

I’ve noticed that most locomotives built from the 80s on have their horns mounted around the middle of the roof, as opposed to 70s diesel locos and earlier, which have them mounted towards the front, on top of the cab. Why were they moved?

It may have something to do with clearances. PRR had some horns off center on some first generation engines because of clearance issues with cab height.

Sound levels in the cab, primarily. When the horn was blowing, it would go well over 85dB in the cab. With the horns back on the long hood, the sound level in front of the train was still OK, but it was much quieter in the cab.

there regulations now that must be followed. formally rrandb

Not only the cab, but the switchmen out on the front “porch” and on the steps/ladders.[{(-_-)}] On my railroad, the horns were moved back and the lights set in the nose at about the same time with ditch lights following shortly after.

I sure noise level is the correct answer. An Industrial Hygiene Consultant I dealt with spent several months in the late 80’s and early 90’s doing personal sound monitoring of crews in CSX locomotive cabs