Engine Sky

From introduction in book:

Engine Sky’s setting is a “soft apocalypse”, where the End Times are a distant memory that cleared out enough of the world’s population to finally bring the planet back to silence, a deep and heavy resting at the end of this species’ existence. No longer will they spread across the planet with endless war —the survivors are too few in number now, and while they have lost most of the technical wonders of the last age, they still have one shred of proof to verify the height of industry their species had reached: The robots.