One of the great things about the Internet is how so much you can learn from the various mailing lists, Internet forums, and personal sites. That's a big change from traditional academic history where finding sources other than published books required moving to the place you were studying and spending a few months interviewing everyone you could.
Getting all the folks interested in particular places - professional historians, local historians, and railfans - together could help open up tons of new data for all communities. I've been chatting with folks from Stanford Spacial History Lab's Living with Railroads project about their new project to crowdsource railroad and western history by helping local historians, railfans, and academics share, collaborate, and build off each other's work. Watch later this year for more on their project, focused on western railroads and specifically the Southern Pacific.
An Experiment: Can You Help? Til then, you can help them understand what each group can contribute via a quick experiment. They've put up a set of Southern Pacific-related photos, and they want to know what you see in the photos. Can you identify the locations? Do you know the context? Can you see specific details that others might miss or might not understand?
To participate, visit their blog, check out the photos, and share what you know in the comments section for each photo.