Arguably the time frame for the C&TS could be from the mid 1920's to the 1950's. Men's clothing styles would change some over that period, but not too much. As you say, suit, tie, hat. In the 1920's and early 1930's the summer hat for many of the business / managerial types was a straw boater. Fedoras for winter, and later on, year-round.
However, I think at this point, the question I would have is how can the fan community, the towns of Antonito and Chama, the Commission, and the states all work to publicize the railroad better. The key is people in seats. Appropriately attired docents etc might be an idea, but it isn't where I woudl put my first emphasis. Advertising, as others have noted, is probably a first thing to look at.
A tip of the ol' fedora to ya....
Charlie Mutschler
-30-