[bbaron63]

I believe in one of the Planet of the Apes sequels, they used a BART construction site, because of how futuristic it looked.

[gojomo]

Pre-opening BART tubes were definitely used for George Lucas's first feature film, THX-1138: https://www.sfgate.com/streaming/article/bart-transbay-tube-...

[dredmorbius]

A Streets of San Francisco episode, starting a very young Michael Douglas, was set in the BART tunnels, still under construction, as well.