Brass Sun

Brass Sun is a series by writer Ian Edginton and artist I.N.J. Culbard (with letters by Ellie De Ville) which runs in the weekly science fiction anthology 2000 AD. It began with book one, The Wheel of Worlds, in 2000 AD progs 1800 to 1811 (2012) and continued with book two, The Diamond Age, in progs 1850 to 1861 (2013). Book three, Floating Worlds, began in prog 1888 in 2014. It has also been reprinted as a US format series in america.

The plot
Brass Sun is set in The Orrery, a completely mechanical solar system, the planets of which are linked by the mass transit system known as The Rails, which are maintained by an ancient religious order of engineers, The Prime Numbers. Societies have branched out in different directions on the various worlds of The Orrery as contact between them has been lost, the notion of a creator figure known as The Blind Watchmaker now denounced as hersey by the religious leaders of the planets. And none of the ruling bodies want to acknowledge the terrible truth, that the Brass Sun which powers The Orrery is winding down, and the outer worlds are already succumbing to the cold which will eventually spelll the end for them all.

A young girl named Wren, native to the icy planet of Hind Leg, is entrusted with a vital mission by her dying grandfather: find the key which will restart the Brass Sun and save them all. Unfortunately, nobody believes her...