[Ironhorse]

If you want more of a postapocalyptic feel I have a suggestion.

Earth reached a utopian level of technology when total war broke out between humans and an unknown enemy. The result is a shattered Earth containing a patchwork of old tech still understood, such as steam engines and black powder, and strange archeotech that is equivalent of magic. A world cybernet exists layered over the real, but is filled with viruses and black ICE that can fry minds. Worse, in some areas the archeotech allows digital demons to manifest as real creatures and living beings to physically enter the cyberdomain.
In cobalt deserts a machine ecology thrives on sunlight and salvage, while the great reefs swarm with live evolving at amazing speeds due to terraforming agents running amok.
Many humans changed their bodies long ago in an attempt to escape their Ragnarok. Their ancestors now exist as hybrids of human and animal, but a select few breed true to their human stock. These "true born" are hated and feared, for they can control the vast powers of the world instinctively, but the power can easily drive them mad, and one small mistake or loss of control can bring about disaster.

In this world a young girl grows to womanhood sheltered at the roots of a once towering space elevator. Her tribe sacrificed itself to bring her there, in the hope that she could learn enough in that place to return the chaotic earth to the paradise it once was. Armed with that knowledge, she leaves her sanctuary to save the world.