Hi,
Although I would like to see a third rail replaced (I'd love to see dual gauge in action and I'd love to see a demonstration of the idler flat at work), I do not yet, repeat yet, see a compelling reason to replace it.
Just for the sake of argument, if negotiations with the SL&RG to run NG steam during the winter at least from Alamosa to Antonito (if not as far as Lava or Big Horn), I would begin to believe that restoring the third rail might reasonable.
With 18, 20, and 1744 in the SG stable and one or two NG locos there during the winter (maybe even Alamosa's 169), a dual gauge engine house (no, I'm not promoting restoring the old roundhouse and backshops even though it would be great), and maybe even a water tower might be reasonable.
It might even be possible for a mixed freight and gauge Antonito turn hauled by one of the mikes and the dual gauge idler as a railfan event. With the dual gauge idler and the dual gauge tender on 494(??), it could be possible.
I'd first try to dual gauge Antonito and maybe far enough to get the the "End of Third Rail" sign so that the idler could be moved to and from its display track.
Although I can not see any reason why, another pie in the sky would be to have a 40 foot container of freight be hauled from Alamosa (or Antonito) to Chama on one of the two 6500 flats. WP&Y moved containers. Crazy to see a modern LandSea container behind a 1903 K-27.
Anyway, time will tell. Very few believed that the C&TS would be saved to start with or that a K-37 would visit Silverton.
Food for thought.
Doug vV