OK, you asked for it. This is my not so humble opinion, and does not necessarily reflect the opinon of the management of this place.
I have had some very memorable night moves across the RR. Riding with Dan on the Eureka was great. Other trips were made in the dark generally because something went bust and either we got real late or we needed an other engine in Antonito in the AM.
I need to point out a couple things, not in any particular order.
The biggest messes I have ever delt with on the C&TS involved derailments or track problems between Osier and Sublette.
The above events happened in the daytime.
There is ZERO access to the RR between Osier and Sublette. There are several radio dead spots. If anything happens out there, for the most part your on your own.
Its hard enough to find the rocks on the track in daylight, let alone in the dark.
Just because the Rio Grande ran trains through the Toltec Gorge at all hours of the day and night doesn't mean we should.
The current route the night time operations use is near a highway for 3/4 of its distance, in case we need to get the public out.
Don't run trains full of tourists through the gorge in the dark if you can avoid it.
I'm stepping down from my soap box now and going into hiding............