Gears

Clockwork is life, the turning of gears drive life forward. Hydro power, steam power, wind power, or man-powered, anything to turn the gears that run a city and make civilization possible.

Trains, airships, and automobiles are all developed by the Gears. The cities are built around giant gears that provide water, and even some electricity to each home; the largest of gears can even serve as public transportation. see: Gear Cities.