The CTA is replacing a 102-year-old viaduct in Evanston this weekend. I think the process is kind of cool. They started Friday evening and they'll finish Monday early in the morning, in time for the Purple Line to take people to work. I suppose it helps that they have an extra hour to work tonight.
This is the result of their first 15 hours or work:
And here's the "before" picture (from mid-August):
I always get a little nervous when the bridge is held up by chicken-wire.