Another option that you might consider is Denver. You can get direct flights from most anywhere on the east coast to DIA. Rent a car and it is really only about 4 or 4 and 1/2 hours to get you to either Alamosa or Antonito to spend the night. Ride the train Antonito to Chama on the next day. Spend the night in Chama which allows you to take in both the evening and morning yard action. Return to Antonito by chugging up the 4% the next day. Then on to Durango or whatever. This also gives you the opportunity to add the Georgetown Loop, Pikes peak cog, Royal Gorge, and Colorado Railroad Museum to your trip.
Food for thought.