We're kind of comparing apples and oranges here. On the one hand we have Link, who was a professional photographer that happened to do a major photo essay of one small niche of railroading for a couple of years. On the other hand we have railfans who happened to carry cameras, whose skills with a camera were varied from the semi professionals (Steinheimer, et al), to the pretty good (Hastings, Moedinger, Jackson, et al) to the point and shoot 3/4's of, say, an Otto Perry - essentially railfans with lots of negatives.
As a community of train crazies we are indebted to all of them but their art, as in any art, is in the eye of the beholder and I don't think we can say definitively that one is better than another. Any more than we could say that a Rons painting is better or worse than a Coker or a Fogg - all of whose I am happy to own and display.
As much as I admire Link's work, I don't think I have a single thing of his. But I do have lots of Steinheimer, Hastings, Jackson and Perry!