I'm tending to lean towards what Rich mentioned. There are a lot of "Railroading" books (with general-type information and photos) in the bargain or "Transportation" sections at the Big Box retailers. Disclaimer: I am probably NOT the "expert" on this because I buy so few books--but the ones that I hear friends talking about, as well as ones that I know that they are in some way collaborating on, tend to be line-specific. Some of those are so anticipated that you'll hear somebody say, "I hear that Joe Sixpackstien is working on a book on the ABCD&E. Can't wait for that one". Rarely do you hear anybody waiting around for a book on the "Railroads of the North/South/East/West"--unless it from a very well-known author with photos that haven't been seen much. Make it fresh and prople will buy it. This opinion is from somebody who is in a "target audience"--which might be the preference of most on this board. If it's to get non-foamers to look at train pictures, make it colorful with lots of nice graphics. If it is to get foamers to look at somebody else's train pictures, make it really unique.