Whether it has historical value really depends on what you are shooting. If you are simply a point an shoot guy taking train photos then it has little historical value. Others are making specific attempts to document things such as search light signals at night. With digital you can do things that were never possible with film and therefore some of these creative endeavors have much more historical value. The searchlights will be gone soon. I don't see nearly that much when it comes to guys focusing on a particular aspect of railroading. This kind of photography has significant historical value even in the digital age.
Dick Dorn