Another useful link, http://www.tpub.com/engine3/en32-1.htm
Any question about any make or model of any locomotive ever built, along with inquiries about why the sky is blue, nuclear engineering, the possibility of intelligent life beyond our solar system, and whether Moses really looked like Charlton Heston with long white hair and a beard should be directed accordingly.
23 17 46 11
edblysardUntil recently, all EMDs were two stroke forced induction engines; GEs are a four stroke design with an exhaust driven turbo charger ... Once the [EMD] engine is up to speed, the turbo takes over the air supply, the blower is used for idle and acceleration, which is part of the reason EMDs load up so fast, there ls little if any turbo lag.
This is including a number of mechanical details indiscriminately, which will cause problems for anyone who doesn't know how EMD turbochargers are constructed. All EMD two-strokes require 'forced induction' for scavenging - the clearing of exhaust through the exhaust valves, and provision of clean combustion air in the cylinder volume for the next compression/power cycle. On the other hand, modern EMD engines also require charge-air compression to make their higher power, similar to how many modern automobile and OTR truck diesel engines use turbocharging. There were some early experiments with turbocharging 567s -- I think on UP; someone like Buslist would know -- but they did not prove successful because the two requirements couldn't be met simultaneously wh a simple wastegated turbo setup and contemporary control technology. Hence EMD's rather clever (if nightmare to maintain) system which drives the turbocharger's compressor mechanically when exhaust volume is insufficient to produce adequate turbine power.
"Forced induction" applied equally well to mechanically-driven superchargers and turbosuperchargers; perhaps a better distinction when discussing EMDs is positive-displacement vs. compressor. The gear-driven Roots blowers are positive-displacement superchargers; the overrunning-clutch 'hybrid' supercharger-turbochargers on turbo 645/710s aren't.
There's a particular quality to the Roots-blower gear noise at idle and low speed/acceleration that is (at least to me) absent from the hybrid-turbocharger sound. In my opinion there is a certain magic to that sound, especially in multiple-unit consists, that is unparalleled in any other locomotive.
The EMDs use what is known as a uni-scavenge system, with the Roots style blower creating the air flow into/out of the cylinder, the “whine” is from the air rushing past the intake/exhaust valves and the blower itself.
If you can demonstrate how air rushing past intake valves in an EMD two-stroke produces a whine, I will send you $50.
I had thought that almost all the 'whine' of the non-turbo engine is the gearing in the Roots blowers; I would expect it to far outweigh any induction noise that the comparably small overpressure involved in the scavenge charging might cause at low speed, and I'd expect that the exhaust noise would mask induction air noise at non-blower-drive frequencies at higher speeds. The Roots blower uses the gears both to drive the rotors and keep them aligned with the necessary precision, meaning that the gears are both robust and heavily loaded - a prescription for unavoidable noise.
A most interesting sound would be that of a 539-powered switcher while flat switching and kicking cars. The engine burbles (along with a large pall of smoke) when the throttle is opened and the cut accelerates, followed by the whine of the turbocharger when the throttle is closed and a car is released to coast into the yard track.
Mudchicken, thank you for the info on those engines. "Whew" I thought my imagination was toying with me.
Y6bs evergreen in my mind
Burbling is the 4 cycle engine ... GE FDL and especially ALCo (251 burble & wheeze)
Growling is the 2 Cycle is the EMD at low speed with the traction motors and d/b's kicked-in on a descending grade.
The” whooping” sound GEs make is from the air compressor, it is an electric driven compressor, the “whoop” is from the start up of the compressor, EMDs use a shaft driven compressor, running off a lay shaft or PTO shaft connected to the crank shaft, which is why some engineers will notch up or rev the engine up when pumping the air for the brakes, the EMD compressor is driven by a geared shaft, speeding up the engine speeds up the compressor.
.....................Has anyone heard an older engine sound like it is (burbling or whistling)? The other sound is a grunting or hunting at lower speed. Any opinions??
Cannonball
Murphy Siding Mookie GE's whoop. At least the older ones do. And they seem to run rougher than their EMD counterpart. The Greenies are still smooth as silk. GE - like itchy wool. And I left out a line for the song we are writing - the trains climbing our grade sound like they are at the foot of the bed, heading down the hall for the bathroom! With apologies to Bruce Springsteen.. At night I wake up with the sheets soaking wet and a freight train running at the foot of my bedAnd oh...... it's too lateOh oh oh it's too late
Mookie GE's whoop. At least the older ones do. And they seem to run rougher than their EMD counterpart. The Greenies are still smooth as silk. GE - like itchy wool. And I left out a line for the song we are writing - the trains climbing our grade sound like they are at the foot of the bed, heading down the hall for the bathroom!
GE's whoop. At least the older ones do. And they seem to run rougher than their EMD counterpart. The Greenies are still smooth as silk. GE - like itchy wool.
And I left out a line for the song we are writing - the trains climbing our grade sound like they are at the foot of the bed, heading down the hall for the bathroom!
With apologies to Bruce Springsteen.. At night I wake up with the sheets soaking wet and a freight train running at the foot of my bedAnd oh...... it's too lateOh oh oh it's too late
She who has no signature! cinscocom-tmw
Murphy Siding Do locomotives sound appreciably different under different humidity and temperature conditions? How do the different conditions affect performance and fuel consumption? Not appreciably different unless there's something wrong with them.
Do locomotives sound appreciably different under different humidity and temperature conditions? How do the different conditions affect performance and fuel consumption?
Not appreciably different unless there's something wrong with them.
Thanks to Chris / CopCarSS for my avatar.
Someone once described GE's as having a "farm-tractor chug". I don't totally disagree, but to me they sound more like an old Ford V8 pickup with glasspack mufflers, kind of a "blap-blap-blap-blap" sound. I can't describe it very well, but I can definitely hear it.
CSSHEGEWISCH GE engines have a sound deeper than anything I've heard on a hawg. FDL's were similar in sound to 251's. A sound that I hear regularly, but especially on summer nights when the windows are open, is the squeal of the retarders on Clearing's hump.
GE engines have a sound deeper than anything I've heard on a hawg. FDL's were similar in sound to 251's.
A sound that I hear regularly, but especially on summer nights when the windows are open, is the squeal of the retarders on Clearing's hump.
Mookie I know two things for certain. I can hear a GE before I can see it. This may be only certain GEs, I don't know. And on a clear, cool nite with no wind, trains pulling the south grade 10 blocks from us sound like they are at the foot of the bed.
I know two things for certain. I can hear a GE before I can see it. This may be only certain GEs, I don't know.
And on a clear, cool nite with no wind, trains pulling the south grade 10 blocks from us sound like they are at the foot of the bed.
zugmann Murphy Siding There's some sort of analogy in there about how my wife isn't mumbling, it's that I'm losing my hearing and I'm blaming her for mumbling .... or something like that. Sigh Mightesometruthinthat,youknow.
Murphy Siding There's some sort of analogy in there about how my wife isn't mumbling, it's that I'm losing my hearing and I'm blaming her for mumbling .... or something like that. Sigh
Mightesometruthinthat,youknow.
It's been fun. But it isn't much fun anymore. Signing off for now.
The opinions expressed here represent my own and not those of my employer, any other railroad, company, or person.t fun any
There's some sort of analogy in there about how my wife isn't mumbling, it's that I'm losing my hearing and I'm blaming her for mumbling .... or something like that. You may be right about the weather conditions transmitting sound. But, wouldn't an engine that had a turbo or blower be receiving a different air to fuel mixture at different heat and humidity levels? In race cars, that seems to make them sound different- or at least transmit the sound to my ears differently.
I'm going to go out on a limb here and suggest that the sounds generated by a given locomotive don't change all that much regardless of weather conditions.
What does change is how weather conditions transmit the sound to your ear.
Early EMD's may not have a turbo, but they still have a distinctive whine - due, I think, to the Roots blower.
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
I've heard SD-70's whine, whistle and purr. Hmmmm.... That might be the start of a country song.
Mookie Hey Bud (Murphy) - those SD70's don't whine. Next to the GE's, they purr! But I must remember that we ladies hear a lot better than 99% of the male population.
Hey Bud (Murphy) - those SD70's don't whine. Next to the GE's, they purr! But I must remember that we ladies hear a lot better than 99% of the male population.
I was out walking tonight and got delayed by a train- darn the luck. It was a rock train on the Dakota & Iowa Railroad and it was moving right along. Their locomotives are old, rebuilt Milwaukee Road Geeps and a few SD-40's. I presume the Geeps aren't turbocharged because the were just thundering instead of the usual whine of SD-70's on the BNSF grain trains. Do locomotives sound appreciably different under different humidity and temperature conditions? How do the different conditions affect performance and fuel consumption?
Our community is FREE to join. To participate you must either login or register for an account.