Murphy's Law vindicated again. The Seattle Monorail has two trains, and last year they managed to collide. To get this to happen was particularly tricky, since the trains run on separate tracks, and there is only one spot on the entire line where a collision could occur—and they found it. You can read about it in this Associated Press article that describes the monorail as a "mile-high, 43-year-old elevated line". Wow, a mile high. Those must've been really long ladders to get people down.
It was supposed to resume operation a few weeks ago, but the reopening was delayed due to a glitch in the emergency-braking system. We can't get anything right around here.