Fantastic. I grew up in Alameda, and wondered just what was inside those buildings. My parents always just said "Fans". While they were right, this really brings it all together.
It's worth noting that the Posey Tube provided the proof-of-concept for building a tube in the bay mud that would be similar to how BART's transbay tube would be built some 40 years later.
This is fabulous. I have been through the tube 10,000 times via car, bus, bike, and foot. I've always wondered what was inside the building. I would love to go on a tour if they are still available.
We are curious too. Just a guess: Maybe the lighting system is based on earlier technologies that (while historically accurate and in keeping with the nature of the tube itself) cannot be easily upgraded for modern lighting or energy characteristics without fundamentally changing the nature of the space and its original design? Some sort of like the ambient light of these tubes in their characteristic orange glow; while others prefer the bright white light of modern LEDs?
