Yes, a great video. Imagine riding a gravity car down the line to Muir Woods, like in the vid. BTW, the railroad had a minimum curve of 70 feet...in O scale, that's 17.5" radius and they ran standard gauge Shays & Heislers and long excursion cars around this.
Yes, I can't hype this book too much! I just got it out again and drooled over the old photos and plans. Some time back, I started to build on O scale, standard gauge model of the Motor Car #1, then thought about a 35n2 model. The car is so wide that it woud need to be whacked on for narrow gauge, might destroy it's looks. For you guys with the old Testors/Hawk Cable Car kits (1:48), here is the inspiration. MT&MWRR ran an old SF cable car as a passenger car, still painted in the car's original colors. Plus other unusual pieces of passenger equipment. And then there are the Shays with "swept back" fuel bunkers. In summation, all I can advise is to BUY THIS BOOK no matter what you model.