*wonders when we will cause universe collapse, by building a turing complete computer system out of vacuum tube valves and ferrite bead based core memory running an approximation of dwarf fortress on it... theoretically, it should be possible to build using the technology shown in game, if we are successful at hydroelectric or wind based electrical generation...*
It would give the jeweler migrants something to do. Ferrite beads being very similar to cabochons, and made of iron ore, like hematite.
("The more you know!", little star flies overhead...)
ferrite beadscore memoryvacuum tubetriodecrookes tubecathode ray tubeFor powered vehicles....
Lead acid batteries are absurdly simple, and hardy. In the simplest form, they consist of 2 lead plates submerged in sulfuric acid. One of the plates needs to be highly oxidized first.
Commercial batteries have several sets of plates wired in parallel to give the "cranking amps" needed to drive high torque starter motors on internal combustion engines. However, a sufficient number of them in parallel will give you high DC voltage, which can be used to drive an EV's high efficiency DC motor, if you don't mind the extra weight. They are the simplest and easiest rechargable battery chemistry to make, (and I don't know about you, but I refuse to mix the reagents needed to make nickel-cadmium chemistry.)
For genuine internal combustion engines, a sand-cast engine block milled out with a manual electric milling machine can be made to run on gassified fuel stock. Just about any organic substance can be turned into "syngas", using an appropriate reactor. However, the equipment needed to make syngas doesn't play well with goblin siegers, and would be very dangerous to keep below ground.
Using refrigeration tech, it would make a great means of eliminating all the thermal waste of the thermionic valve based computer....
syngasIt could concievably be routed through pipes for murderhole flamethrowers with an electric spark gap igniter.... but since carbon monoxide is a primary component, I would be loathe to use it, or route pipes carrying it through or inside the fortress. Very much a "do this above ground" enterprise.