I prefer the open car whenever possible, but you just have to be prepared and expect that you're going to get dirty. Riding the C&TS in the early 1990s I saw this guy and his very attractive girlfriend come back to the open car to ride. She was wearing an expensive looking white fuzzy sweater, Said sweater looked light gray with black flecks by the time we reached Antonito.
I'm always amazed by the people who don't realize that riding behind a steam engine means you stand a good chance of getting dirty and your odds go way up in the open car.