OK, this thread is already wandered off narrow gauge to preservation in general (perhaps material for a nice RYPN article) so I dont feel too bad mentioning some of the historic traction lines that around but the preservation has not quite happened. Perhaps the only cases are the cable cars and J line streetcar in San Francisco, and Pearl Brewery in San Antonio. A number of places exist where the lines and numerous facilities are intact, and perhaps some "native" historic equipment might even be on the property, but active use with it or demonstration (ala C&TS) really isn't happening. This would include Boston, Philly, Toronto, East Troy, the Iowa Traction Railroad and the South Shore Line. (my opinions)
Please forgive the non-steam non-narrow gauge inclusion. (Don't shoot!)