Watching Frank Howarth and his son build that model of the bi-level vertical-lift bridge, I got to wondering about different movable bridge designs. I'd never seen that unique bi-level variant before; what other solutions have engineers come up with when a bridge has to be moved out of the way for a boat to pass?
Turns out there's at least a dozen different kinds of movable bridges that have been realized around the world. Helpfully, Wikimedia Commons contributor Y_tambe has animated their transformations:
Vertical Lift Bridge
Rolling Bascule Bridge
Got a favorite? I love how the Rolling Bascule design completely prevents any Blues Brothers or 2 Fast 2 Furious bridge-jumping moments. And no, I will not be judged by you for watching and enjoying 2 Fast 2 Furious, what I do on my own time is my own business.
Thanks again to Y_tambe for putting in the time to create these! You can click on his/her bridge page to see static shots of the real-life versions of these bridges alongside the animations.