What sound is use for a diesel

[Morebassman]

How do I find out what prime mover to download for an engine? I have know idea what sound to download for my fleet!
How do you reseach to figure this out? I have done seaches but I didn't get any results.
Also the same thing goes for the horn.
I have a

NS SD80-Mac
BNSF SD70-Mac
BNSF GE AC4400CW
Amtrak P42
E6
PA

[William Brillinger]

I like Wikipedia for this.

A google search usually will get you to a Wikipedia page for a specific locomotive.
IE: search for "SD80-Mac"  https://www.google.ca/search?q=SD80-Mac

The first result is https://en.wikipedia.org/wiki/EMD_SD80MAC

The first line of the article reads: The SD80MAC is a 5,000 horsepower (3.7 MW) C-C diesel-electric locomotive. The model uses a 20-cylinder version of EMD's 710G prime mover

Usually the wikipedia page will list the prime mover in the spec section on the right side of the page.

Prime mover    
EMD 20-710G3B-ES(80MAC)
EMD 20-710G3C-ES(80ACe)

So for the SD80MAC I would use the EMD 710 ULT file.