Less obvious about car #15 is that it's one of the newest cable cars. It's painted in a bright yellow color scheme originally used on the Powell-Mason line from 1894 to 1902. Built from original blueprints, it was placed in service in June, 2009.
This design is one of the oldest of any San Francisco cable car, originating just a few years after the Powell-Mason cable car line opened in 1888. Today, according to the San Francisco MTA: "the Powell-Mason line is oldest transit line in America still operating on its original route with its original type of motive power and its original type of vehicles."