First, welcome to the hobby. Lots of great people to meet and enjoy your interests with. Millions of train freaks out there.
Regarding your question, I wouldn't be too surprised if Metra didn't have some sort of public relations piece which provided the very basics. You should try contacting them. Remember, post 9/11 things are going to be viewed with one degree of suspicion or another.
I'd also suggest some Google searches. "Metra locomotives", "Metra engines", "Metra power", "Metra diesels", "Metra operations", etc.
There are many guys out there who know from a little to ALL about these engines. Take some time and you'll learn a lot. Then you'll find out you're just BEGINNING to scratch the surface of this great hobby.
Have fun!
John