I made a visit to the Cable Car Museum, a small place but well worth seeing. I hadn't reaslised that all the cars are being pulled around by a couple large cables that run round the whole route throughout the city. You see them in operation as they travel in, round the huge wheels and back out again. San Francisco's is the only mechanically operated cable car system in the world and they can't get rid of it as it's now a registered national treaure , or something like that. Either way they can't touch it - hurrah.