The world of Solace exists in a historical context similar to late 19th-century America. Industrialization is transforming a once agricultural society into one that relies heavily on machines. Machines are everywhere in The Mark of the Dragonfly. They are a recurring motif that relates to the theme of Hybrid Identities. Just as none of the major characters in the story is an ordinary human, the society in the novel has been hybridized into a human-machine model. Anna is the most obvious example of this hybridization process, but Piper might just as easily be viewed as part machine. Her emotional affinity to mechanical devices practically fuses her with them.

There are other examples of human-machine interdependence later in the story. The 401 is an example of a vital transportation link between the Merrow Kingdom and the Dragonfly territories. Without the train, commerce would be impossible. The economies of the two kingdoms depend on the trains that run between them and the tracks that connect them.

Even the bandits who rob the train depend on machinery to carry out their thievery. They use gliders and motor-powered aircraft to attack the train. Conversely, the train depends on yet more machinery to repel the invaders.