I like a lot of the suggestions I've seen in this thread: especially the movable walls/crusher type idea. Also quite keen on the conveyor-belt idea to move large quantities of rock from A to B - combine this with an "endless lift" and you can pretty much move masses of anything from anywhere to anywhere regardless of distance/z-level.
• An endless lift is a continuous belt wrapped around two axles - 1 at the top, 1 at the bottom. A set of teeth line the inside of the belt, these engage over pulleys fixed to the powered axle. And, before anyone yells at me that it's too "modern"
* I'd like to point out that Vitruvius reported that our good friend Archimedes built something similar circa 236BC!
*To be honest, I don't quite get the hang up on 15th century technology. Just because something wasn't known to European technology (
i.e.batteries, steam engines, gunpowder, optics, and paper to name a few) circa 1400 - or had been forgotten/not used - doesn't mean that it absolutely shouldn't appear in DF.
- Elevator - Archimedes circa 236BC
- Batteries - circa 600AD (Babylon Battery)
- Steam Engine - Hero circa 100AD
- Gunpowder - China circa 800AD
- Paper - again China, circa 200AD
- Optical Lenses - Assyria circa 700BC
...and so on. There's probably a whole slew of other stuff the Chinese, Babylonians, Greeks, Romans, Assyrians, Persians, and other folk knew that got lost in the Dark Ages or was forgotten simply because nobody could see a practical use for it. Since we're dealing with a fantasy game here - let's not get too hung up on 1400 as a "cut-off" for technology.
What
is important is the use(s) that the technology is put to.
I can easily see Dwarves super heating steam using magma and using it to spin an axle - just like you would with a capstan or water-wheel.
Electricity - electric lighting and powered equipment? Probably not. Electro-plating was probably what the Babylonian Battery was used for and there's no reason some smart dwarf couldn't have discovered the same process that Brugnatelli is credited for in the 1800's.
The same is true for other forgotten technologies. I can see a use for optics straight away: a Dwarven lookout on a high tower with a telescope? Ideal for spotting invading Goblins