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.
i'm not aware of anyone replacing digital relays after 10 years.
The SEL relays we buy have a 10 year warranty and are designed to last at least 25 years: https://selinc.com/company/quality/
