SCREAMING SD40-2

[AC6000CW]

WHY DO THEY SCREAM AT RUN 8?

[wctransfer]

Umm, take off the caps, and please, use better grammer. Anyway, its the highest notch they can go, obviously they are trying harder and harder to get it moving. Its pretty logical, i mean, the harder they pull, the louder they get.

Alec

[AC6000CW]

I do know that but what causes that pitch.

[wctransfer]

The turbo is the main thing that makes it do that. They have that "squeel" that all loco's with turbo's have. Someone else can probably go a little more in depth, but the Turbo is what your hearing.

Alec

[AC6000CW]

what is a turbo ?[%-)]

[wctransfer]

Umm, its a HP and Tractive effort upgrade you might say. I really cant explain what a turbo is , but it makes it more powerful im assuming , and numerous other things. But , i forget what model was the first one to be equiped with a turbo, maybe the GP35, or maybe the GP20, not sure.

Alec

[Anonymous]

QUOTE: Originally posted by wctransfer

Umm, its a HP and Tractive effort upgrade you might say. I really cant explain what a turbo is , but it makes it more powerful im assuming , and numerous other things. But , i forget what model was the first one to be equiped with a turbo, maybe the GP35, or maybe the GP20, not sure.

Alec

It's a trubine hooked up to the exhaust system, similar to a super charger.

[AC6000CW]

does it sound like this.
http://trainiax.0catch.com/slrsept232002-3004.wav

[wctransfer]

Off topic, but look at that contributed drawings part of that link you posted,im in there.
Thanks James for clearing that up.
Alec

[trainboyH16-44]

The GP20 was the first turbocharged loco, with a small round thing on the fireman's side.
Wow, AC6000, I love that recording! You should post that on the "Have you ever heard a loco in notch 8" thread! It wa one of the best things I've heard all day, and the subwoofer made it SOOOOO GOOD!
Matthew

[tpatrick]

Alco FA/Bs were turbocharged. They had a very high pitched whistling sound that I remember clearly from watching freights on the Erie back in the 50s. They normally ran in four unit lashups. Like many Alcos they tended to smoke heavily due to turbo lag while accelerating. I am sure they predated the GP20.

[Anonymous]

The turbocharger, is a air compressor of sorts.
It takes the hot exhaust coming out of the engine, and uses it to turn an air compressor, that turns at a very high rpm ( causing the screming sound you hear) compressing the air coming into the engine.

More air in, more horsepower, more exhause out, more tubo boost ( amount of air pressure over ambient air pressure) more whine.

They use the hot escaping exhaust which would othwerwise go un-used, to make more power.