That's why the Georgetown Loop has success. It is closest to Denver and right next to a major highway. Also it is a short ride, meaning the service can be maintained with less equipment than other railroads. The ROW is less expensive to maintain because of its size. The more track an attraction has the more expensive it is.
The Manitou & Pikes Peak also enjoys good location, other major tourist attractions and history.
Sorry C&TS fans, its location is a two-edged sword. The scenery is a major but it is out in the middle of nowhere.