Scrap Iron Haven 6: A Decadent Triangle.. Scrap Iron Haven, #6

In the shadows of the industrial city of S. I. Haven, the collapse of a train-shaped universe has left behind more than just ash and memories. Mark Taper, a young private investigator, finds himself navigating a reality where the line between fiction and life has dangerously blurred. When a fictional reconstruction of the brilliant but cold Dr Vostok appears as his new homeroom teacher, Mark is forced to confront the impossible...
characters from a dead world are surviving in his own by any means necessary...even if it involves stolen blood and borrowed organs. But the doctor isn't the only ghost in the machine. A psychotic killer named Lamp Light has also crossed over, leaving a trail of bodies in her wake as she seeks a twisted version of affection from the only man who truly understands her. Amidst the chaos of homicidal "fictional" rivals and the ever-present threat of the local "Closet Serial Killer" Doremi, Mark is approached by Saar, a frail girl whose existence is as fleeting as the unseasonable snow falling over the city.
Tasked with a final request from the girl, Mark must venture into the abandoned mining badlands to uncover the truth of the Ember Children's origins.