This is a vintage railroad switch mechanism, which I shot at a railway museum not too long ago. A switch, at it's simplest, is just a way to get a train or railcar from one track onto another-lining the points to send it on the main line or onto an adjacent track. Of course, things get more complicated when you have multiple tracks, different directions, and things like storage tracks, sidings, and plenty of other things I can't think of at the moment. Many switches are operated by powered mechanisms, but at one time they were all manually operated by mechanisms similar to this one. Plenty of them are still in use, too.