Sandy, that is a great schematic. Where did it come from? That should be on the wall of every electric shop.

http://xkcd.com/730/ from

http://www.xkcd.com/

Which also rewrote the national subway map and offered it up as a poster:

http://xkcd.com/1196/large/

http://store-xkcd-com.myshopify.com/products/subways

See also:
http://xkcd.com/878/

Every comic has what's called "rollover text"--roll your cursor over the comic, and a sub-text pops up, usually giving yet another laugh. The rollover for the last one I listed above is particularly relevant to railfans.

Brother Mitchell,
I was unaware that either you had been cleared for that particular protect or, in the alternative, it had been declassified.
GME

I think I worked on a machine wired to that schematic today...