To use an analogy, I know cars, I build cars, I drive cars, I work on cars, and I still go to shops, and races, and demonstrations, and read material that I not only know but probably have read several times before.
The point is, even if I knew EVERYTHING about this railroad, I would still visit a visitors center, or a "museum" not only hoping to learn something new, but also to refresh the old. So I belive that the visitors center would be filled with people who already know the story as well as those who dont.
This could also be a good place for more sales and donations to be made.