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?
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. [:X]
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.
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]
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.
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!
Paul - back in the 50’s, I lived 2 blocks closer than I do now and we had a “real” hump with a sorting yard. Summer and no a/c, with windows open, we would hear the retarders, the loud speakers for the hump and then an occasional really loud crash as the cars would run into each other. It was loud enough to make you jump!
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.
[8][8] At night I wake up with the sheets soaking wet
and a freight train running at the foot of my bed
And oh… it’s too late
Oh oh oh it’s too late[st] [8][8] []
…[:^)]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??
Until recently, all EMDs were two stroke forced induction engines; GEs are a four stroke design with an exhaust driven turbo charger.
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.
Once the 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.
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.
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