Michael Healy recently published a book about the history of San Francisco’s bay area rapid transit system (BART).
Even in the 1960s, the cost of BART seemed crazy. On top of that, it used new, unproven technology. The cost reminds me of today’s mega-projects like the California high-speed rail.
BART required some complicated political maneuverers to get off the ground. For example, the BART board got the California legislature to pass a measure that reduced the required voter support from 66% to 60%. BART didn’t have enough voters for 66%. This reminds me of the soda tax in SF didn’t pass until it was reworked to require only 50% rather than 66% of the vote.
Once the initial stake was driven, nothing could kill the project. Even though it eventually required far more funding, it still got finished.
After the initial project was completed, it lacked any coherent vision other than “operate, and maybe grow some day”. Consequently, nothing much happened to BART over the past 40 years. Contrast this with San Francisco’s Muni which keeps expanding at a slow but steady rate.