Reading progress update: I've read 51 out of 352 pages.

Railhead - Philip Reeve

Station Angels were a sort of harmless energy which flickered sometimes in the wake of trains. They might look a bit like ghosts of gigantic praying mantises, but everyone knew that was just the way human brains interpreted some sort of interference that got dragged through into the normal universe when K-gate opened. But these Angels, rather than just wandering and fading as an Angel should, seemed to be echoing Raven's movements somehow, as if all three of them were dancing to the same movements.