Today — Super Bowl Sunday — we can be grateful for Bay Area public transit systems. It’s likely the buses and trains will be crowded, but they should make the whole day more tolerable for many people.
My father used the Key System to move between San Francisco and Oakland when he was a young man. He found it very efficient, but added that the most memorable part was the odor. The train cars themselves didn’t smell, but at that time untreated sewage was dumped directly into the Bay. Well, maybe the trains got permeated in time. We can research that later.
The Key System was taken out of service way before we had Bay Area Rapid Transit (BART).
This 7×7 article from November 2012 doesn’t mention the stench, but it’s fun to read anyway.