Accel trolley wire copper-silver casting

So shape is part of your function, and microstructure imparts function too. [Tom holds up a slice of continuously cast trolley wire.] This is a slice from a continuous casting. Anyone been on the Acela train between Washington and Boston? It's an electrified train. Electrified trains either get their power from a live third rail on the ground, or they have a trolley wire up above. This is a piece of the trolley wire that was supposed to hang between New Haven and Boston when they were upgrading for the Acela. It has the shape so you have little pinches that can hold the wire. It was supposed to be made originally from a casting of very high purity copper-silver alloy. This only has a tenth of a percent silver, so they left it for me — I can still use it, it's not worth much. But it has a particular structure; you can look at the grain structure on this longitudinal section.