Identi-charts for diesels

Recently, I have been trying to post photos on some of the rail sites. The photo quality demands are tough enough, but I am really a steam guy, and I’m not sure how to I.D. some(most) of the diesels I’ve photographed. Where can I find a simple place that will list what a GP-7 is, or what the different types of Alco’s might look like? Thanks, W&NB

I don’t know what’s available in cyberspace but try the various editions of “The Diesel Spotter’s Guide” and the “Field Guide to Modern Diesel Locomotives”. They will provide you with everything you need to know and then some.