You don't have to just read about historic railroads or only take train rides (although riders pay the bills!). You can become a volunteer. Some of the jobs that you can do are:
...or any of dozens of other tasks or jobs.
Here are some places where you can volunteer. These are all Museums with excellent reputations. These would be great places to learn about historic railroading
Mid-Continent Railway MuseumMy favorite. Restore Steam Engines or Wooden Coaches. Be a Train Crew Member
San Diego Railroad MuseumLots of equipment on display. Steam operations.
Friends of the Cumbres and Toltec Railroad The longest and highest narrow gauge railroad.
Colorado Railroad Museum They have a fantastic collection of narrow gauge equipment.
Illinois Railway MuseumSteam, Electrics and (!)Diesels.
Minnesota Transportation MuseumStreetcars, Steam Engines and a Steamboat.
California State Railroad MuseumGreat displays and an operating steam train.
B & O Railroad MuseumThe most historically significant collection of railroad equipment in the United States.