I went to the 24 Hour Fitness in the Castro yesterday, and they are in the midst of “upgrading” the showers. I’m not sure what that means, but I will probably never find out since I refuse to shower there.
Currently, the back of the locker room with the shower area is walled off with plywood, and they have fiberglass shower enclosures rigged up in frames made out of 2×4s and plywood with all the pipes exposed so people can shower during the construction.  These makeshift showers are sitting in the sink area, each with a really cheap looking curtain (possibly just a piece of fabric?)  across the front of each shower. They have wooden steps (also plywood) so you can get up to each unit.  Because the  shower situation is taking up half the locker room, during the afternoon rush it was so crowded I felt like I was getting changed on a crowded bus.