Many years ago, when I was in college, I rode my bicycle down to the yard to watch an SG steam train go through. As was typically the case, the train was late. My parents were concerned about approaching darkness, so they drove after me in the family station wagon (yes, I did say that this was a long time ago). I have a brother who is MUCH younger than I am - in fact, he was just learning to talk when this story took place. My Dad parked the car a bit closer to the tracks than he intended, and thus the whole car felt it as the train finally went steaming and puffing and tooting past us. There was silence in the car for a moment, and then my brother said "More!".
In his case, I wasn't around much, and no one else bothered to cultivate this potential interest, but I believe that there is a lesson in all of this. Ordinary railroading, especially ordinary steam railroading can be thrilling to almost any youngster. It may take some kind of gimmick (shorter rides would be a real plus here, but they would make sense only if they are priced to make money) to get some families to Chama and/or Antonito. However, the real selling point will always be the hundred-year-old product with all of its inate excitement.