GE's and ALCO's do have a turbocharger whistle, but I guess it's not as loud. It's usually possible to pick out the turbocharger whistle from any turbocharged engine, even in a car or bus. Granted, EMD's seem to have a particularly noticeable whistle! The whistle is from the blades of the rotor passing through the air at an extremely high frequency--which occurs regardless of whether the engines are 2- or 4-cycle. (I suppose the exact pitch would depend on the rotating speed of the turbo and the number of blades.)
All the recordings I have of working MLW M420W's have a whistle, but it's quieter and higher-pitched than the whistle of the EMD's (I had to search to find one where the whistle is really noticeable). There's no "whine" like the EMD's, but then again that's not from the turbo.
Here's a recording of 2 M420W's and 2 GP40's--between 12 and 16 seconds into the recording, the MLW's pass in a chorus of very high-pitched whistles from the turbos (something like 6300 Hz). At 17 seconds the fan whine of the EMD's is most apparent, and at 18-19 seconds is the turbo whistle from the EMD's, slightly lower-pitched than the MLW's (around 4300 Hz).
http://trainiax.0catch.com/slrsept2000-3579.wav
All the recordings I have of working MLW M420W's have a whistle, but it's quieter and higher-pitched than the whistle of the EMD's (I had to search to find one where the whistle is really noticeable). There's no "whine" like the EMD's, but then again that's not from the turbo.
Here's a recording of 2 M420W's and 2 GP40's--between 12 and 16 seconds into the recording, the MLW's pass in a chorus of very high-pitched whistles from the turbos (something like 6300 Hz). At 17 seconds the fan whine of the EMD's is most apparent, and at 18-19 seconds is the turbo whistle from the EMD's, slightly lower-pitched than the MLW's (around 4300 Hz).
http://trainiax.0catch.com/slrsept2000-3579.wav
--Michael Eby
--http://trainiax.net
--http://trainiax.net
