Cable cars are so much fun! I can't believe i'm an SF native that has only ridden them twice. :/
that museum is great fun. the last time i visited i was with friends from out of town. we stuck our heads in near the work area and one of the workers called us over and showed us around the area where they re-work the cable cars. we left with a set of cable car brakes (which are made from fir).
how loud is it in there? just from the photo it looks as if it would be really loud :p