HUTCH 7.62 Wrote:
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> Miss the sound of a Nathan P-3
>
> Enjoy.
>
> Which begs the question. Why do horns on newer
> locomotives sound so awful?


Blame all the NIMBY's and laziness on the part of locomotive manufactures and railroad shops. New FRA regulations came out in December 2004 that specified a maximum as well as minimum decibel requirement for locomotive horns. Lots of older horns that sounded good suddenly were too loud. There are fairly easy ways to quite down a horn, most of these involve feeding it a regulated air supply at reduced pressure, not the full main res 140 PSI. Regulators are another maintenance item than can fail, and require changes to the air supply. It was far easier for locomotive builders to ask horn manufactures to just make a new horn that met the requirements. Thus the new K5HL for GE, and K5LLA for EMD. Both of these horns play notes that are an intentional discord. They don't sound great but they DO meet the FRA regulations without having to alter the locomotive air supply.

PJ Wrote:
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> I'm not sure of the year but sometime a while back
> Nathan quit building P type horns to fine
> tolerances or tuning, instead just turning them
> out however they came out of the shop, with
> casting irregularities, etc.
>
> PJ

Fairly close. In the late 1970's Nathan outsourced the casting of the P horns to new foundries. The external length of the bells remained the same, but the point where the flare started changed on most of the bells. As a result the P horns after 1978 don't play the same notes as the ones before. P horns are still being made and can still be purchased new, they just don't sound like they used to.

toot Wrote:
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> Why are horns mounted far far back on the roof
> instead of up front where you can hear them

Makes it much easier on the locomotive crews. Lots of older railroaders are now nearly deaf from years of sitting two feet under a horn for 10-12 hours on end. Mounting the horn further back doesn't do much to change how other well people hear it, but does significantly cut down on noise in the cab. One downside is that often the horn is now very close to the exhaust, which fills the horn up with soot making it fail sooner.

MaFarnz