One of the great things about The Internet is that people share things of interest. One of the things that sucks is when you can’t remember who it was that originally shared Something Cool, and you can’t give them credit.
This is one of those things. It’s an old film about the 40 San Mateo line Muni once operated from San Francisco to San Mateo. The line was discontinued, only to see much of the same right of way used for BART. If it seems strange that those in charge would rip up a line only to rebuild it decades later, well, it is, but that was the post-war era for you.
It is interesting to watch, if only because you’ll see some historical footage of San Francisco, and the Peninsula. It is interesting to note how much of Burlingame, near what is now the Caltrain station, really hasn’t changed much in the last 75 years. Anyway, enjoy!