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Silly question about EMD F-units

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Silly question about EMD F-units
Posted by John-NYBW on Tuesday, January 4, 2022 2:49 PM

I don't know why this hasn't occurred to me before since I have been acquiring EMD F-units, both F-3s and F-7s, from a variety of manufacturers for decades. All of them have one rooftop horn facing forward and the other backward. Since they all have this feature, I assume it is based on the prototypes. My question is why would one of the horns would face backwards?

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Posted by gmpullman on Tuesday, January 4, 2022 3:22 PM

John-NYBW
Since they all have this feature, I assume it is based on the prototypes. My question is why would one of the horns would face backwards?

Well, might seem obvious but one was for moving forward and one for backing up.

 F_horn_NYC by Edmund, on Flickr

 F3_manual by Edmund, on Flickr

Then there's the situation where some roads were still using flagmen. They would have to be called back to the caboose when the train was cleared to move. The rear-facing horn could be used to "throw" the sound toward the rear of the train.

 Santa-Fe_FT-cab by Edmund, on Flickr

Some engines were equipped with a dual-volume whistle valve for yard or road use. Two lanyards so the engineer could choose the louder "mainline" horn or less air volume for close-in yard work.

 Nathan_Valve by Edmund, on Flickr

Many roads had operating conditions or preferences of the mechanical department or state laws that affected the choices and options of air horn use over the years. Lots of variables out there.

Good Luck, Ed

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Posted by cv_acr on Friday, January 7, 2022 9:38 AM

Lastspikemike

That's the Doppler Shift horn, a half tone lower that sounds back towards you at that grade crossing the locomotive you were watching just crossed. 

 

That's not what Doppler Shift means or how it works.

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Posted by cv_acr on Friday, January 7, 2022 9:45 AM

Also, while a number of railroads used single-chime horns like this on early diesels, not all did.

What you see on most diesels today (and on some other railroads even back then) are 3- or 5-note horns, and you'll notice that usually the horn bells are arranged in a 2/1 or 3/2 forward/backward arrangement. The whole horn blows the same chord all the time, and sound is directed in all directions.

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Posted by wjstix on Friday, January 7, 2022 9:51 AM

Plus, some railroads that bought diesels with single chime 'blat' airhorns in the 1940's-50's later changed them out for multi-chime horns. I know Missabe Road's SD-9s (not F's, but same generation) came with single chime horns, which (after experimenting with Hancock air whistles) the railroad came to replace with 5-chime horns.

Note too that for a long time all model railroad manufacturers just put the one-forward/one-backward single chime horns on all the F-unit models they made, regardless of whether that was correct for that prototype engine and railroad. In recent years, some manufacturers try to make sure their models have the correct 'prototype specific' details...but not all manufacturers do that, or only do it on their higher-end more expensive models.

Stix
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Posted by 7j43k on Friday, January 7, 2022 10:40 AM

cv_acr

 

Lastspikemike

That's the Doppler Shift horn, a half tone lower that sounds back towards you at that grade crossing the locomotive you were watching just crossed. 

 

 

 

That's not what Doppler Shift means or how it works.

 

 

THIS time, I think he did it on purpose and knowingly.
 

 

Ed 
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Posted by 7j43k on Friday, January 7, 2022 10:47 AM

wjstix

Plus, some railroads that bought diesels with single chime 'blat' airhorns in the 1940's-50's later changed them out for multi-chime horns. I know Missabe Road's SD-9s (not F's, but same generation) came with single chime horns, which (after experimenting with Hancock air whistles) the railroad came to replace with 5-chime horns.

Note too that for a long time all model railroad manufacturers just put the one-forward/one-backward single chime horns on all the F-unit models they made, regardless of whether that was correct for that prototype engine and railroad. In recent years, some manufacturers try to make sure their models have the correct 'prototype specific' details...but not all manufacturers do that, or only do it on their higher-end more expensive models.

 

 

Prior to about 1950, all locomotive air horns were "singles".  And there were a good many of those, at the time.

The guy who thought it would be good to have multiple bells was Robert Swanson, whose work led to Nathan.

Here's a link to (I'm surprised) the Wikipedia article on locomotive air horns:

 

https://en.wikipedia.org/wiki/Train_horn

 

So, back when Varney and Globe were first producing their F's, they pretty much nailed the air horns.

 

Ed

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Posted by SeeYou190 on Friday, January 7, 2022 11:37 AM

7j43k
THIS time, I think he did it on purpose and knowingly.

I am sure. Here goes the Mike-Merry-Go-Round.

 

Ick!

Step 1) Post something you know is incorrect.

Step 2) Wait for the right answer.

Step 3) Say your answer was correct even though it was not.

Step 4) Enjoy the argument.

Step 5) Go back and edit your original response.

Step 6) Explain how you are never wrong.

I am glad Ed (G M Pullman) gave the OP the correct and informative answer.

-Kevin

Living the dream.

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Posted by SeeYou190 on Friday, January 7, 2022 12:08 PM

gmpullman
The rear-facing horn could be used to "throw" the sound toward the rear of the train.

I have heard this before.

Were cabooses ever equipped with a signalling device to send a signal back to the locomotive?

-Kevin

Living the dream.

DrW
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Posted by DrW on Friday, January 7, 2022 12:19 PM

SeeYou190

 Were cabooses ever equipped with a signalling device to send a signal back to the locomotive?

-Kevin

 

Yes. Before radios became common, the Santa Fe used wig-wags to communicate from the caboose to the locomotive.

JW

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Posted by dehusman on Friday, January 7, 2022 12:54 PM

SeeYou190
Were cabooses ever equipped with a signalling device to send a signal back to the locomotive?

Yes they had a whistle, typically on the rear platform next to the brake valve.

Dave H. Painted side goes up. My website : wnbranch.com

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Posted by 7j43k on Friday, January 7, 2022 2:33 PM

The sound-equipped Athearn Genesis cabooses have horns/whistle.

 

Ed

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Posted by gmpullman on Friday, January 7, 2022 3:59 PM

 BPRR 1002 by Todd Dillon, on Flickr

Many, but not all, NYC wood cabooses had distinctive hi-lo whistles permanently mounted to the cupola:

 NYC_caboose_cupola by Edmund, on Flickr

Depending on service assignments. Probably most road cabooses did not have permanent roof-top whistles. I've seen examples of Leslie A-125 horns mounted up there, too.

The "peanut" whistles found on the end platforms would not sound loud enough to ever reach the cab of a locomotive but "might" get the attention of an automobile driver at a crossing during a backup move. Those whistles were usually combined with an emergency brale valve so the air could be dumped. These were also attached to "pigtails" that could be connected to the rear air hose.

 NYC_wood-caboose by Edmund, on Flickr

[addendum]

SeeYou190
Were cabooses ever equipped with a signalling device to send a signal back to the locomotive?

I've witnessed times when one of the rear-end crew, when it was time to signal the engineer they had everything in place to proceed, would make a brake pipe reduction using the brake valve in the caboose (not the emergency valves) this would alert the engineer, by watching his BP pressure gauge, that he could then proceed.

Cheers, Ed

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Posted by Overmod on Saturday, January 8, 2022 9:41 AM

On the Jersey Central in the early 1960s, the big six-motor RSD Alcos had two horns.  The rear-facing one (the engine being set up to operate long-hood-forward) blew a lower note and was used to distinctively communicate with the caboose or to call in flagmen.

I think the 'Doppler shift horn' was a joke; the idea would be to make railfans think the train was going faster than it was.

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Posted by tstage on Sunday, January 9, 2022 11:01 AM

Lastspikemike
cv_acr
Lastspikemike

That's the Doppler Shift horn, a half tone lower that sounds back towards you at that grade crossing the locomotive you were watching just crossed. 

That's not what Doppler Shift means or how it works.

Yes, I know.

On a model locomotive the Doppler shift would not be noticeable anyway, speeds are too low and speed of sound doesn't scale....

I'm pretty sure humour is not prohibited by forum rules.

If it was indeed a joke, it would be helpful if you used an emoji to convey that - e.g. Clown, Wink, Smile, Wink & Grin, or Laugh.  Otherwise, you run the risk of making folks Grumpy because your intended meaning was not understood properly Tongue Tied.

Tom

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Time...It marches on...without ever turning around to see if anyone is even keeping in step.

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Posted by wjstix on Monday, January 10, 2022 9:46 AM

Lastspikemike
Looking at photos of EMD FT Unit 103 which was built originally as a drawbar connected ABBA unit the one large horn faces "forwards" on each A Unit. There appears to be a smaller horn also facing forwards. Later photos showing preserved 103 as an AB Unit (customers abandoned the four unit drawbar connection very early on) show the more usual two horns on the A Unit, one facing each way.

Actually FT 103 were two A-B sets. The A-B sets were connected by drawbar, but the B units had regular couplers at the other end. They were sometimes split up for testing. For example, Great Northern used one A-B sets on runs between Mpls-St.Paul and Duluth-Superior.

BTW that's why FTs had the odd unbalanced look, the trucks at the ends where the drawbar was located were very close to the ends of the body; the trucks at the other end were set back on the A and B unit creating an overhang to allow for couplers.

http://research.nprha.org/Diesel%20Diagrams/EMD%20FT%205400A-5410D.jpg

Later F units - both A and B - had the trucks set equal distance from the ends on both ends, so could have couplers at both ends.

Stix
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Posted by NittanyLion on Monday, January 10, 2022 10:59 AM

gmpullman
BPRR 1002

This guy's horn wasn't for signaling back to the locomotive. It was installed around 2007. That caboose is used in the multi mile backup move between East Butler and ARMCO/AK Steel/Cleveland Cliffs. They use it to honk at grade crossings. 

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Posted by wjstix on Monday, January 10, 2022 2:59 PM

7j43k
So, back when Varney and Globe were first producing their F's, they pretty much nailed the air horns.

True, but even in recent years some manufacturers have offered F-units in later paint schemes (like Amtrak or BN) that still had the two single-chime horns and other 'generic' detailing from when the model shell was first made, even though by the time that paintscheme was used the real engines had multi-chime horns. 

Stix
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Posted by gmpullman on Monday, January 10, 2022 3:00 PM

NittanyLion
This guy's horn wasn't for signaling back to the locomotive.

Never said it was.

Kevin asked if there were ever horns mounted on cabooses. I provided a photo of a caboose with air horns.

gmpullman
The "peanut" whistles found on the end platforms would not sound loud enough to ever reach the cab of a locomotive but "might" get the attention of an automobile driver at a crossing during a backup move.

Then Kevin asked:

SeeYou190
Were cabooses ever equipped with a signalling device to send a signal back to the locomotive?

Then JW mentioned the Santa Fe Wig-Wags.

MY reply to Kevin mentioned using the brake pipe pressure to "signal" the head end, otherwise it was hand signals or if necessary, the conductor had to walk up to the engine.

Regards, Ed

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Posted by Tin Can II on Tuesday, January 11, 2022 2:49 PM

A retired Santa Fe conductor told a story online about riding the rear platform of a Santa Fe caboose several miles on a shove move down a branch line; using the "peanut whistle" to signal grade crossings.

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