Here in Iowa, the DOT has a handy map of the railroads, active (listing which railroads utilize the trackage) and abandoned (listing which decade the line was abandoned).
From now on whenever I add a railroad bridge, I will just call it "bridge, railroad". I can let the railfans on here fight it out...
I now have an app that monitors this website, that notifies me whenever the term "CSX Railroad" is changed. It changes it back because it is the correct term, then emails me to let me know it is changed back. Saves me a lot of time. Thank goodness for technology!