I have not visited a yard that has a genset yet. What is the sound these thing produce when pulling? My guess is they are going to sound like a truck or a bull dozer. In reality what do you think of the sound?
The NRE ones sound like semi trucks and the RailPower ones sound like buses. They are actually really quite and you have to really listen to hear them.
Ron
http://www.railfanrails.com