EMD Turbo Howl - EMD 710 Series

[@Goetterdaemmerung86]

That’s thrilling and ominous, also very eerie how the locomotives lights peer through the trees

[@kenpalmer1965]

Exactly! My thoughts too!

[@icomsltd]

*stuck on the tracks nightmare fuel*

[@railfan220]

Thanks for the upload! I've been on a KZbin crusade to collect as many examples of turbos howling as possible. On another video of an ES44AC with this fantastic sound, someone explained that it comes from an imbalance in the turbocharger. GE turbos spool in run 8 at about 22,000rpm, and EMDs (710s) a little less than that because of the difference in the red lines between the two (1050 vs 900ish). When perfectly balanced, there isn't too much to hear, but from my understanding, if a blade gets bent/chipped or the bearings cause any sort of oscillation, our ears render that vibration as a 365 Hz (less for EMDs) pitch. Like you've told so many other people, it's not the radiator fans or anything else. While you can hear them, they lack the depth of sound that the turbo has, not to mention the fact that the howl clearly comes from the exhaust stack. I'm still curious why this happens with more frequency to EMDs. I have found plenty of examples of GEs doing this as well, but not as often as EMDs. To some degree, it's a function of use and age. It could be that GE turbos have to be replaced more often, so they don't often get to this point. Or maybe EMDs have a particular turbo part that wears out more frequently. The mechanical clutch on EMD turbos could certainly be a source of imbalance. Thanks again for uploading! Hopefully you enjoyed my novel titled, Unsolicited Ramblings of a Procrastinating Man. Lol. -Cam

[@mbta1051]

railfan220 did you make a playlist yet called “turbos howlin”? 🤣😂 Also, where is that video of the ES44 with the howling? I have yet to hear a GEVO make any sort of sound.

[@pootispiker2866]

The clutch on an EMD is nothing more than a one-way bearing

[@Goetterdaemmerung86]

Quite right, the fans would've blown apart LONG before they could make any noise like this. Also note, the doppler effect doesn't lie, it occurs right as the exhaust port passes the camera.

[@ellisjackson3355]

22000 rpm that's more like a centrifugal supercharger speed. I thought the turbos on these spooled faster than that.

[@pootispiker2866]

@@ellisjackson3355 at higher speeds the turbo wheels have a tendency to separate rather destructively

[@TheRrxing]

That brings back great memories. My brother and I had a favorite spot near a few curves to watch Penn Central trains back in the 79’s. Hearing the engines before seeing the train was just as exciting!

[@martihill3611]

The deep howl is actually the main alternator. Pumping out 3000KW on EMD locos, they really scream. I listen to all the racket in load test a few times a week. That's a perfectly normal sound. Light exhaust smoke, they are running good.

[@sicilian12345]

It's actually the cooling fans Lol.

[@JaZu]

I live West of Cleveland near a CSX line. There is a ton of traffic in both directions. I generally decompress at night with a whiskey and a cigar on the porch and it is amazing how far away you can hear those things. I mean the horn is loud, but the engine and components itself is very loud. I was stationed on a CG boat that utilized ALCO 251C’s. Those baby’s were perfect to rocking you to sleep at night.

[@trainiax]

No, this noise is not the main alternator. If it were, all EMDs of a given model would make the same sound - and they don't. Note that the second unit in the consist (an SD60E) is not making any such whine despite being mechanically very similar to the lead unit. This is a well-known occurrence with turbocharged engines - not just EMD units. Carbon deposits or slight physical damage throw the turbine rotor out of balance. The pitch of the whine in this video is 300 Hz - which corresponds to a turbo speed of 18,000 rpm (typical - if slightly slow - for a 710 in notch 8).

[@eoinpkav152]

All of you stfu, jesus.

[@thatmatty231guy]

@@eoinpkav152 m8 iTs ThE FlUx CaPaCiTor TruSt Me I GoT Tra1n SimUl8r

[@user-lm8fx6kc1b]

There must have been 70,000 frogs in the second video, guess they are also EMD 710 fans.

[@gordtvradio3465]

It’s so fitting this was filmed at night So spooky Love it Reminds me of my childhood

[@greglaplante7593]

That’s looks and sounds so beast at night. The lights in the dark.

[@lelandmiliken430]

Seems like everyone is arguing over what is making this awesome sound. Just enjoy it, whatever is producing it.

[@a-lineproductions631]

Leland Miliken turbos of an EMD unit makes that sound.

[@floridianrailauto9032]

@@a-lineproductions631 Generator

[@a-lineproductions631]

Wolf Nigga radiator fans

[@mbta1051]

A-Line Productions the crew whining about trackside foamers 😂

[@floridianrailauto9032]

@@a-lineproductions631 An actual railroader said it's the generator

[@TheNikkirock]

some of the BEST train video i've ever seen. Love the angles and nighttime shots. Like I was there...goosebumps. Keep 'em coming.

[@easternroutemainlinevideos6823]

the EMD 710 series sounds pretty badass

[@woods840]

Peepers and EMDs at full throttle on an early spring evening. Heaven.

[@PC10.8]

Wow! Sounds amazing! But I can basically FEEL the mosquitos biting through my screen!

[@SuperWorldRailFanProductions]

That would creep me out, especially at night!

[@icomsltd]

This was the first sound to creep me out as a kid. I lived in a small town along Hwy 99 in California just 10's of yards from the track, It's long and strait so you could hear it WAY out coming from north or south. When you cross the track you could see them MILES out and it looked like pure nightmare fuel. It had a sound that made you instinctively duck and hide.

[@williamgreeter1855]

I always love to hear that sound in the 80s I heard a lot of 645 16 cylinder howl at run 8 now I also love to hear the 710 16 cylinder howl at run 8 as well

[@boompa92]

Love it. I just heard this sound from the Trout Brook valley and Westminster Junction here in St. Paul. I find it calming.

[@JonBvideo]

Sounds like a combination of the turbo and the traction motor blowers. Possibly more the blowers.

[@keithode1737]

The howling is the main generators, not the turbo or traction motor blower. .

[@tarmac2001]

Never heard the main generators having any kind of cooling fans.

[@a-lineaficionado1000]

Found this spot the other day and it is amazing

[@Cnw8701]

3:30 is eerie as hell!

[@josherickson6862]

Not gonna lie I’d be kinda concerned if I heard that in the middle of the night, but a 645 wide open emits a deep roar that is unmistakable

[@TankCrusher210]

This is the sound of the radiator cooling blowers on the roof of the locomotive. Listen to an SD series locomotive during a load test. You will hear this exact sound start and stop periodically as the cooling system switches these fans on and off as part of the control loop that regulates engine temperature. For example: kzbin.info/www/bejne/bpLceKephtWGh5I It is evidenced that this sound is entirely unrelated to the engine's turbocharger by the fact that it can start and stop independently of engine and turbocharger speed. Furthermore, it cannot be related to the traction motors, as the traction motors are disconnected during a load test, while the sound is still present. These are very similar to the fans used to cool the dynamic brake resistors, and produce a nearly identical sound.

[@NSAaron]

If it is one thing that makes the SD40's a unique sounding locomotive is the radiator fans being so loud that it can be heard almost over the engine. Indeed in that load test video you hear the dynamic brake fans spool up to cool the resistors and the three radiator fans spool up once the engine water thermostats trigger the fan relays to turn on. Having worked on the SD45 at Oak Ridge, the fans come in sequentially just as in that video. I have heard SD40's in full throttle with the turbo howl going along with the fans. One you get to the SD60's and SD70's (probably the SD50's as well) the cooling fans changed and were much quieter. I have heard an SD70 in full throttle without the turbo howling and I could hear the fans running on the long hood. They sound much different than this. Also I take into account EMD turbo chargers are mechanically driven till about notch 6 or so of throttle. A clutch system free wheels the turbo from the mechanical drive and becomes more like the turbo you would hear on a diesel truck where it is driven by exhaust pressure.

[@csulaguy1833]

That K5LA also sounds pretty damn good!

[@NSAaron]

I've got a diagram of the cooling system for an SD45, and has the wiring schematic for the fans. Since the locomotive has shutters the circuit triggers them open once fan 2 comes on. The temperature sending units that trigger the fan relays are located on a manifold that checks the temperature of the coolant on the output of the compressor, which I find strange.

[@NSAaron]

I'm not sure about the 1 fan cutting out as needed. It maybe for a specific road as some had theirs wired up a bit different.. The general wiring diagram shows that each comes in sequentially and drops out sequentially.

[@caderamsey8878]

I've heard this noise coming from Locomotives at full throttle, what is this "Howl?"

[@Med0sproductions]

Caterpillar EMDs man ! They dont play around when it comes to those diesel engines. That is music to my ears and it gives me a rush of excitement hearing those emd engines coming through the woods!

[@AUSSIETRAINDRIVER]

Ewee Entertainment caterpillar has stuck With the 2 stroke because their own engines can't compete.

[@floridianrailauto9032]

Uh, no they haven't? The new SD70ACes are 4 stroke engines.

[@AUSSIETRAINDRIVER]

@@floridianrailauto9032 previously I meant, and. That's only Because the 2 stroke can no longer meet emissions. Now are The SD70s using actual caterpillar 4 strokes, or the previously mothballed emd H engine?

[@tenseven1398]

I thought that was the horn until i heard the actual horn blare. That is absolutely and insanely cool!

[@PaulsDMVRailroadsandAviation]

For those who think it's the fans (I thought it was too), if you listen and watch closely as the train passes in the first clip, the Doppler effect of the howl comes before the radiator fans pass the camera location. The turbo probably vibrates a lot at high rpm's, if that's true then that's what the howl is

[@1918dawson]

ur trippin lol

[@nb44647]

Doppler effect at 10mph? Hardly...

[@Goetterdaemmerung86]

Quite right, also it's absolutely possible for a doppler effect to occur at that speed, for crying out loud you can hear a doppler effect from someone cycling or jogging past you

[@caderamsey8878]

It’s either the train is in full dynamics or it’s the radial Exhaust fans.

[@djtrainman2]

It’s in full throttle. I can tell by how the engine sounds and the way the fact that they are moving slowly and right before the first clip ends I can tell that it’s going uphill

[@pup9et]

Beautiful landscape. Thanks for the vid

[@rogerdavidson217]

I done this for almost 30 years however I love it.

[@franklinde9015]

We supply OEM parts for GE/EMD/ALCO turbocharger for 20 years. Blades for almost all EMD models

[@SethMethCS]

3:30 Do you hear the undertones? Very ethereal to say the least.

[@Goetterdaemmerung86]

Indeed, sounds like wheels grinding against the track?

[@Nethanel773]

Wow, sounds just like the howl of the old GP40's! Like it!

[@isakjohansson7134]

Those trains are so dope! And the horns! 🤩

[@gordtvradio3465]

This is the best train video on KZbin

[@bnsf8610]

Normal EMD sound of a 710.

[@V0latyleUSMC]

That's the radiator fans. While the turbo is gigantic, you can't really hear it at high RPM. You can when the prime mover is in idle or low notch, as the high pitched whistling sound, but once it starts building boost it decouples from the drive (like a supercharger with an overrun clutch) and spins freely.

[@NSAaron]

You are right about the turbo being clutched. The free wheels from the mechanical drive once you get to about number 6 throttle and become exhaust pressure driven to notch 8. However, I know the howl is not the radiator fans. I've been on bridges many times and listened to those go under and the source is definitely coming from the stack. I've also had a Mechanical Department employee at NS tell me that the turbo is what generates that howl on those units. Our SD45 at Oak Ridge has a bit of a howl to it, although not to the degree as this, and walking on the long hood you can distinguish pretty easily that the howl and the fan noise are coming pretty different places. Not all the locomotives with 710's howl like this anymore and some that do howl at different pitches. Fans on these engines can be heard sometimes, but are much more silent compared to what the SD40's had. Not to mention if it was the fans, the howl from unit to unit would be roughly the same pitch and a lot of them are not.

[@V0latyleUSMC]

Ah. Thanks for the info. I figured it would be cooling fans, as the fans for the dynamic resistors and the radiators are very similar, so it would only make sense that they'd make the same noise.

[@NSAaron]

Anytime! I not sure if the following is correct, but my small mechanical experience with locomotives is as follows. The radiator fans are 3 phase power and their speed change with engine RPM through the generator. I'm not sure if all locomotives that use electric fans are 3 phase, but I know from a few I have helped work on were. As for the dynamic brake fans, their speed varies with traction motor speed. DC motors on this engine would make the fans DC I would have to guess. Some of the electrical energy from the motors in dynamic braking used to power the cooling fans for the resistors while the rest is used by the resistors to convert it to heat.

[@martihill3611]

It's actually the main alternator. They really howl under high amp loads on EMDs. The cooling fans really make no sound at all. They are low rpm and you can't even tell when they are running. Sd70macs have exterior cooling fans for the phase modules and they are loud, but nothing like the big alternator.

[@trainiax]

Shadyn - No, it's not the radiator fans. EMD Q-type fans introduced in the late Dash-2 series use unevenly spaced blades and supports located above (rather than below) the fan blades, specifically to eliminate the fan whine common on older units. The whistle you refer to is common to any turbocharged unit and comes from the turbo impeller blades. There is a similar high-pitched sound (on EMD units only) from the turbo gear train. But the whine in this video is from the turbo rotor itself - the rotor being slightly out of balance while turning 18,000 rpm. The dead giveaway comes when a 645-engined unit makes the same sound. The 645 turbo has a 16-blade impeller that makes a more pronounced whistle than the 710 (which has 17 blades). When the turbo whine is present on the 645, it varies from unit to unit and is unrelated to engine speed - but the pitch of the whine is always exactly 16 times lower than the impeller whistle.

[@TheMNrailfan227]

I heard this beautiful sound just now irl

[@westernrailroadvideos99]

It's not the turbo, fans, blowers, traction motors or dynamic brakes. The howling sound is the AR20 main generator on the leading SD70M. Listen to the part at 0:44 where they throttle back from run-8, the howl immediately changes pitch because the main generator is bolted to the flywheel off the prime mover. Any change in engine speed (throttle) changes the RPM of the main generator and thus changes the pitch of the howling. SD60Ms, some SD70Ms and SD9043MACs have particularly noisy main generators.

[@NSAaron]

I may have to give our SD45 a listen by the main generator next time she's out and see if that's what is doing it or not. She has a little bit of a howl in 8. I still doubt the main generator is what is making that. I have been on bridges when these units go under in 8 and overwhelmingly the source of the howling in straight down the stack. I've had shop guys tell me that is what makes that noise especially during a load test.

[@oakcreekrailroadproduction3907]

And dont forget the sd80macs they make noise too

[@davidandyvonne06]

This how it used to sound on the Saluda Grade....music to my ears!!!

[@modeltrainproductions3167]

love that sound. definitely knew when he was coming didn't u

[@EdmontonRails]

you'll get better night footage if you film at 30FPS instead of 60 when it gets dark

[@NSAaron]

I never thought about that actually. Thanks!

[@silicon212]

It's not the turbo that you're hearing. It's the traction motor cooling fan.

[@icomsltd]

Those engines running purely on the cries of lost souls.

[@timmcneil1536]

music to my ears...aaaah yes! Thx I needed that.

[@a-lineproductions631]

Reminds me of conrail EMDs

[@The3751FAN]

It comes from the radiator fans spinning at full rev.

[@NSAaron]

On SD40's and such it sounds similar. I have heard the fans on the SD70's when the turbo isn't howling and they don't sound like that. They are much quieter than the SD40's. The turbo howl you hear is much louder than the cooling fans.

[@Goetterdaemmerung86]

@@NSAaron Yup, I'll admit I thought it was the fans for the longest time too, but others explained it well enough and now I'm convinced it is indeed coming from a vibrating Turbo. Not to mention, the fans would surely blow apart before they could ever even make this amount of noise. You can notice a similar phenomenon with a Dremel tool with a large cutting disc, if you exceed the RPM limit of the disc slightly, it can vibrate real bad and violently and make a very loud noise much like the one heard here. I recall you saying you've had heavy duty mechanics tell you that the noise comes from the Turbo correct?

[@dstrdm]

I hear some 645 and 710, 20 cylinders on the engine room of tuna seiners and the whistle of the turbo is clearer, you can also hear the valves working.

[@ronbrennan4632]

Aaron nothing beats the sound of a diesel engine doing what it does like no other engine pulling under full fuel even my Lil 0m 616 dzl is so unique thanks for your videos ron brennan rdzl om616

[@supertyfon1736]

I bet that sound can carry 20+km in an open environment and some could probably reach 100 db at 100 ft this one could be 90-95 db at 100 ft.

[@modeltrainproductions3167]

ur right Chris the dynamic braking uses the cooling fan directly behind the cab frame on all locomotives that's the sound of it whining up and down.

[@NSAaron]

Dynamics use a set of resistors to exchange the power generated by the traction motors as heat. The fans help vent this heat to atmosphere to keep the resistors from overheating. I believe some the current generated by the traction motors during dynamic braking is spent through the cooling fan motor as well.

[@modeltrainproductions3167]

Thanks for the additional info

[@TankCrusher210]

The radiator and dynamic brake fans on EMD locomotives are driven by AC induction type motors if I am not mistaken. Unless the electrical power recovered by the traction motors is first inverted into to AC and then fed back into the auxiliary AC power system using a synchronous-type (grid-tie) inverter, I don't see how DC dynamic braking voltage could power the AC fan motors. It is certainly possible from a technical standpoint, but I have never heard of such a system actually implemented in a locomotive. It would require careful coordination between the companion alternator and the inverter in order to balance both power sources on a single load like that. Without coordination (normal constant-voltage type output regulation), one source could potentially fight with the other by trying to take up all of the load. It would be very enlightening if someone could find an official technical manual that covers the dynamic braking system in an SD-series locomotive.

[@NSAaron]

I've got some stuff on GP-30 control systems which would be similar enough. I'd have to look in the manual I once had for the SD45 we have at Oak Ridge.

[@trainiax]

@@TankCrusher210 The radiator fans on EMD units are AC and driven by the auxiliary alternator - which is why on Dash-2 and earlier units, they spin at slightly less than 2x the engine speed. Later units have multiple fan speeds. But the dynamic brake fans are DC - including on units with AC traction motors, in which case the variable AC coming from the motors is rectified to DC for the dynamic brake grids and fan motor.

[@spacecalander]

They look like they are in notch 8 on a grade. although it was hard to tell with the stupid horn blowing right as they passed by. second pass in the dark sounded just like the old SD45T-2s on Donner Pass i used to watch. First time i have heard the 710 sound like that, which is nice because the 645 is gone.

[@gastonforde2121]

AWESOME VIDEO AND MAN THAT SURE IS A LOUD TURBO HOWL!

[@4trainproductions]

Imagine your taking a nice little strole on that road, then all of a sudden you hear this:

[@TemplarKnight1177]

Wether the howl is from the turbo or the MG, how is it affecting the working environment? It's a nice sound for a few minutes, but what if you hear that high pitch howl hour after hour day after day? The howl reminds me of an air raid alarm.

[@Hunter_Dawso]

Sounds like a set of tunnel motors charging up the hill.

[@JishyFishy4106]

It sound like a mixture of TF33 with a TF39/F103/F138

[@Jennifer-K5LA]

Sounds almost like full dynamic brakes with a heavy load moving down grade. I live on a steep grade and hear this exact sound a lot from trains moving down grade, but not so much going up..thats usually more of a deep thunderous droning exaust roar with a mechanical whining and a slight dash of turbo shriek from the EMDs....The GEs just bark and growl and launch plumes of smoke and fire going up grade 😮

[@danielkennedy1524]

Outstanding! Got to get up there and video as well! thanks!

[@steveconnell791]

That sound is actually the cooling fans for the traction motors.

[@stanpatterson5033]

The bulk of the "howl" heard is the traction motor cooling blower motors. Also, the rad cooling fans are going flat out, and all the traction motors are whining and protesting, and yes, in there somewhere, the turbocharger is, no doubt, wailing too. Some of the modern GE's kick up quite a racket beyond the rumble and chug of their prime movers... the blower motors drown out everything and sometimes if the thing has the "Clean Rail" option, it's blowing out a hiss of air too.

[@joshuafurborough811]

Most likley in dyno coming down that grade

[@1600Z1]

I live by the tracks of CSX in Ohio. I am two miles from a 25mph curve. I can hear this same noise after the prime mover has been throttled down but the dynamic brake cooling blowers kick in. the time between when the engineer lets off and starts coasting the locomotives are so quiet just in idle then the cooling blowers kick in and that is the exact noise you hear. High static pressure fans...makes this sound. Moves more air but is noisy.

[@VincentMMoore0]

Great video, thank you for posting.

[@jacobtrumpore5752]

I heard a trailing GE do it once also, but I couldn’t say on what It is, my guess is something that is directly connected to the prime mover since it stays the same pitch until they adjust the throttle, I would think the compressor would be every now and then and the fans the same.

[@antidisestablishmentariani6182]

i hear this howl quite often with GO transit's MP40PHs

[@hemipaterson2486]

We have Chinese made locos here in NZ that have insanely loud fans, especially in notch 8 on the grade past my house, so although a lot of people are claiming it's dynamics or traction motors I can vouch for hearing that exact sound from our locos under power. You have to admit though, it's a very similar sound to a lot of locos dynamics.

[@hemipaterson2486]

Whoops, just read "Turbo Howl". For some reason I thought the title referred to fans. My bad.

[@hemipaterson2486]

So I'm thinking now, what I've been hearing is actually turbos.

[@user-lm8fx6kc1b]

The is howl is actually the cooling fans for the traction motors.

[@rogerdavidson217]

he got it back when his slack ran out

[@RDC_Autosports]

it’s in full dynamic run 8 All 3 cooling fans are on that’s what you hear

[@davidbass7593]

Generators loaded to the max!!

[@pauldilworth3297]

Top Drawer. American railroading at its best.!

[@cr1901]

Looks like the engineer saw you at both locations (hence the horn)?

[@BenjaminEsposti]

My thinking is it's the dynamic brake cooling fan. Watching various videos of this, there seems to be one fan in particular which is the loudest. It's the one right behind the cab. In fact, more recent locomotive versions have this noisy fan all the way at the back of the loco. My guess is this is because of the sound level. I dunno why they wouldn't change the fan design so it's not as loud ...

[@NSAaron]

Dynamic brake cooling fans on the SD60's an SD70's don't spin fast enough to howl that high of pitch. The only time that fan would be turning would in dynamic brakes or load test.

[@rogerdavidson217]

No that # 8

[@rogerdavidson217]

Pulling

[@danielkennedy1524]

EMD!!! rock on!

[@parteibonza]

Sounds like the fromt end of my porsche when the cooling fans are on high. 😂

[@ht24d64]

I hate to inform you that the howl you are hearing is not the turbo but the traction motors howling

[@stanfordwalker1292]

That's power

[@vancepomerening4794]

Boy, the nerve of disturbing the sex life of all those froggies!

[@vishc645]

Referring to these as the "Angry SD locos!"

[@emmanuelofori869]

Its not Turbo sound, this is constant howl which suggests an electrically powered motor powering some cooling fan.

[@tylerl6400]

Sounds creepy in the dark.

[@michaelrichter8973]

It's all three fans on radiators plus motor fans that cool traction motors plus turbos probably not Dynamics because it's headed up hill but I think the same fans that cool the dynamic brakes also cool the grids that power the traction motors also electrical components tend to get hot when under heavy loads!!

[@menardsgaming1220]

nothing howls like an EMDs turbo

[@ChickennGritss]

Nice footage

[@1991kdogg]

what think is the cause of the derailment in Spring City

[@Med0sproductions]

this is so damn cool!

[@easyamp123]

it's the fans, it's not even a question.

[@nerktwins7023]

Those locos are in run 8 throttle position. and not in dynamic braking.

[@dennisyoung4631]

“… he hears the *EMDs howling,”*

[@danielsebring6220]

Folsom's turbo blues!!

[@thisischetan]

The horn was similar to disney sound. 😂😂 You shud listen to WDP-4's horn and engine sound. Then comeback here. 😂😂😂

[@TheStefan188]

seems 2614 in combination with 6982. my knowledge isn't that well about these trains.

[@mbta1051]

TheStefan188 yes and the 2614 is the loud one

[@motoslayer6859]

That’s cool

[@8thnotchjoe2000]

There is no such thing as a "turbo howl" this is the fans and radiators trying to prevent the engine from overheating and altering performance or blowing the motor up. The fans are on the top of the engine next to the exhaust stack and airhorn and they make this sound when they are spinning at maximum potential. Some engines have their fans kick in like this even before the 8th notch is applied, some do it in 6 and 7 and when in 8 it becomes the loudest and fullest of potential. The sound is coming from the top of the engine and towards the rear .

[@McCracken_9]

cooling fans?

[@rogerdavidson217]

He came off the throuttle to #6

[@rogerdavidson217]

And got it back when the slack was out.

[@djtrainman2]

2:30 you can clearly see that it is uphill

[@tylerl6400]

its the cooling fans.

[@dustbowlhammer7119]

If he's on a down grade I would say that was the Dynamic brakes in action.

[@joshuafurborough811]

100% be in dyno

[@awaken77]

It's sound of electric fans for cooling radiators and dynamic brake grid. Turbo in EMD not distinctively heard at full throttle. Here is good example of 710 turbo spin-up when train achieving speed : kzbin.info/www/bejne/jmqZq6qferp1f5o

[@heyherb]

Nice..

[@coreymcdowell3471]

Not turbo just cooling fans

[@Iconic_maya9]

Oh my god

[@rogerdavidson217]

Its a hard life

[@AzTrailRider57]

I can't claim to be an expert but that doesn't sound like any turbo I've ever met. Could it be the generator/traction motors making that noise? That would be my bet.

[@NSAaron]

The noise, from what I can tell, is coming out of the stack. I know at least on an EMD that the turbo is mechanically driven up to about notch 6 or so of throttle. After that the turbo is driven by exhaust pressure as the turbo is clutched and free wheels from the mechanical drive. I would imagine somewhere in that setup is where the howl is generated.

[@martihill3611]

It's the main alternator. They all sound like that in full power. More so on a SD70MAC. SD70 ACE uses a different alternator with a different rectification system. The whine actually comes out the front of the alt.. if you opened that door on the engineers side, it would blow your ears out.

[@westernrailroadvideos99]

Savage!