Imagine a world where steampunk has been taken to a highly advanced level. Gears and cogs and all that fun stuff, on both massive and minuscule scales. Now destroy that civilization. Earth split asunder, fire falling from the sky. Needless to say very few survived and all knowledge of the technology was lost.
However, those who rebuilt were surrounded by the ruins of that past civilization. Only the toughest artifacts survived, and much of it is broken parts. But from them the people of this world reborn gained two major things, a source of high quality materials, especially metal; and a basic understanding of technology. The civilization would have grown with the basic ideas of steam tech, gear and cogs and all that.
Now given that this world has artisans capable of handcrafting parts and adapting those they can scavenge, what would the tech of this world look like? Think feudal government, swords and arrows, large class of people toiling in the fields with a few specialists and elite on top. What would be some of the first advancements and what would be the ramifications.