Dave Jones of EEVBlog recently tore down an analog navigation computer used on the B52 if you want to see inside a mechanical computer of this type https://www.youtube.com/watch?v=hzGaO4Kdz2Y

My dad's eng degree is in electromagnetic mechanics . He graduated just as mechanical relays (actually analog computer controlling a relay) in the power grid were being replaced by electrical ones.

A few interesting things he points out:

-Throughout his career nothing has had the longevity of these mechanical devices. As late as the 2000s he had projects replacing mechanical relays installed in the 30s. Digital becomes obsolete and needs replacement in ten years when the manufacturer stops support.

-If a Turing machine can be implemented as an electrical circuit, and an digital computer is, ultimately, an analog circuit; then an analog circuit can do at least as much as a digital can. It's just impossibly more difficult to do.

Earlier discussion: https://news.ycombinator.com/item?id=7419837

Those instructional videos in the article are extremely well done. They seem to be part of a longer film, does anyone know if it can be found online?

For more info read the very good "Between Human and Machine: Feedback, Control, and Computing before Cybernetics" by David Mindell.