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Locomotive horns question

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Locomotive horns question
Posted by eolafan on Thursday, March 4, 2021 5:19 PM

I've noticed on locomotives (most) with five "chimes", seemingly all chimes face backwards and only one small chime faces forward...why? Seems to me it should be the opposite. Thanks.

Eolafan (a.k.a. Jim)
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Posted by Lithonia Operator on Thursday, March 4, 2021 9:44 PM

That fifth one just hasn't been blown around backwards yet.

Wink

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Posted by wjstix on Monday, March 15, 2021 1:14 PM

Do you have a link to a photo of such a set-up?

Keep in mind the "front" isn't necessarily where you think it is. Particularly in the first generation of diesels, quite a few railroads (New York Central, Great Northern, Canadian National) considered the long hood of the GP and SD diesels as the front.

Stix
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Posted by CSSHEGEWISCH on Monday, March 15, 2021 1:48 PM

A common arrangement that I've seen is three bells pointing forward and two to the rear.  Western Maryland had a full set pointing in each direction on some of its locomotives.

The daily commute is part of everyday life but I get two rides a day out of it. Paul
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Posted by emdmike on Monday, April 5, 2021 6:29 PM

I have seen this on many current ES44's and other current day motive power.  Not sure why either.  Most power uses Nathan K5L something horns these days with only a few getting Leslie products horns.   Just like NS taking the remaining high hoods back to P3 horns instead of the twin P5 Nathan horns they once carried.  Some of the recent rebuilds on the NS have sported brand new Leslie RS5T horns, which are more espensive over the Nathan K5 horns.  Alot depends on the shop doing the work, the shop foreman's prefereance in horns ect or even just what the shop has on the shelf at the moment the engine needs a horn installed or replaced.   As long as it makes noise and meets FRA Db requirements for loudness its all good.   Mike the Aspie

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Posted by blue streak 1 on Tuesday, April 6, 2021 11:51 PM

Then you have the new Acela-2s horn of European nature.  Although expect them to be replaced wonder if a different horn to signify a HrSR Acela to persons standing nest to tracks or maybe just use when operating at a certain speed or higher ?

Maybe it would at least warn Schummer ?

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Posted by Overmod on Wednesday, April 7, 2021 11:30 AM

blue streak 1
Maybe it would at least warn Schummer ?

Be fair.  It wasn't Chuckie, it was the other half of Mr. Schanoes' "Schumenthal" that needs better horn awareness... 

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Posted by FanOfTheRail on Monday, April 12, 2021 10:39 AM

eolafan

I've noticed on locomotives (most) with five "chimes", seemingly all chimes face backwards and only one small chime faces forward...why? Seems to me it should be the opposite. Thanks.

 

The horn that you are seeing is the Nathan K5HL, used on General Electric GEVO locomotives. It is not a mistake that all bells except the 3 bell are reversed. It is to meet FRA requirements that the horns must not exceed somewhere around 110 DB. Apparently, it doesn't matter to the FRA how loud the horn is when it is facing the long hood end. The Nathan K5LLA, mostly seen on the EMD SD70 series is one of the louder locomotive horns. I believe both horns were specifically designed to meet FRA noise requirements, but the K5LLA actually ended up being much louder. Also, for some reason, the 1, 3, and 5 bells are faced forward, with the 2 and 4 bells being reversed. I'm not sure why the K5LLA was allowed to have more forward-facing bells because it was the louder horn. I hope this helps.

~FanOfTheRail

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Posted by Overmod on Monday, April 12, 2021 11:38 AM

It's exactly 110dB now.  For those who are interested, here is the FRA's basis for 96/110dB:

https://railroads.dot.gov/environment/noise-vibration/horn-noise-faq

 And this is, I believe, the report that led to initial NPRM etc. for the horn rule:

https://railroads.dot.gov/elibrary/determination-sound-level-railroad-horn-regulatory-compliance

It was my understanding that horns before this time were built to produce very loud "emergency" sound, above 132dB, with valve design allowing the horn to be blown at some lower intensity (the GE P42 is explicitly built this way and I believe uses the Amtrak K5LA).  It does occur to me, without checking, that reversing bells to get a lower SPL in the 'tested' zone while nominally retaining the 132dB or whatever as-built spec solves the 'noise' concern... while retaining the ability, say in a court, to provide that a manufacturer or engineer sounded the loudest possible emergency signal to cut through noise-cancelling headphones, loud music in cars with double-pane glass, etc.

 

 

 

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Posted by zugmann on Monday, April 12, 2021 4:33 PM

Overmod
while retaining the ability, say in a court, to provide that a manufacturer or engineer sounded the loudest possible emergency signal to cut through noise-cancelling headphones, loud music in cars with double-pane glass, etc.

I know some amtrak engines have the quiet-loud dual setting, but on our freight engines, we only have one level.  They took away our old-school manual valves when they installed the PTC stuff (probably becuase PTC can blow the horn, so they needed an electronic valve).

 The opinions expressed here represent my own and not those of my employer or any other railroad, company, or person.

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Posted by FanOfTheRail on Tuesday, April 13, 2021 1:51 PM

Overmod

It's exactly 110dB now.  For those who are interested, here is the FRA's basis for 96/110dB:

https://railroads.dot.gov/environment/noise-vibration/horn-noise-faq

 And this is, I believe, the report that led to initial NPRM etc. for the horn rule:

https://railroads.dot.gov/elibrary/determination-sound-level-railroad-horn-regulatory-compliance

It was my understanding that horns before this time were built to produce very loud "emergency" sound, above 132dB, with valve design allowing the horn to be blown at some lower intensity (the GE P42 is explicitly built this way and I believe uses the Amtrak K5LA).  It does occur to me, without checking, that reversing bells to get a lower SPL in the 'tested' zone while nominally retaining the 132dB or whatever as-built spec solves the 'noise' concern... while retaining the ability, say in a court, to provide that a manufacturer or engineer sounded the loudest possible emergency signal to cut through noise-cancelling headphones, loud music in cars with double-pane glass, etc.

 

 

 

 

Huh, that's how Amtrak engineers quill the horn. I wasn't sure because I thought they had an full on/full off electronic horn valve, but that explains it.

~FanOfTheRail

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