This is a fun documentary on the Disneyland Railroad, which up until 1982 was independently owned and operated by Walt Disney and the Disney family, apart from Disneyland. It goes through how the railroad has grown and changed over the years. All of the trains are restored narrow gauge trains built in the late 1800s and early 1900s for use on real railroads and short lines. Originally converted to run on diesel instead of coal, today they all operate on biodiesel converted from the used cooking oil used in the park. There's also detail on the block signaling system used in the park. Much like the monorails, this isn't a cheeky theme park ride, it is an authentic, genuine railroad.
Monorails always have a soft spot in my heart, and thus here's a nice series of documentaries about the Disneyland and Disney World monorail systems. While not the first working monorail system in the US, it is the oldest continually operating system in North America. Walt Disney had intended for them to not just be a theme park attraction, but a shining example of the future of transportation. The Disneyland monorail was first expanded to serve as public transportation from the Disneyland Hotel across from the theme park. Several years later, the monorail was meant to be the marquee piece of public transportation for Disney's futuristic society, the Experimental Prototype Community of Tomorrow (EPCOT). Unfortunately the fulfillment of his dream was never fulfilled after his passing, but Disney has never treated the monorail as anything less than infrastructure critical for both theme parks' operations.