Eberron - Return of the Lich Queen
The societies of Eberron developed not through the advance of science, but by the mastery of magic. This concept allows for certain conveniences unimagined in other medieval timeframes. The binding and harnessing of elemental creatures makes airships and rail transport possible. A working class of minor mages uses spells to provide energy and other necessities in towns and cities. Advances in magic item creation have led to everything from self-propelled farming implements to sentient, free-willed constructs of wood and stone.