This article is concerned with travelling detectives in two different but related senses. On the one hand, it considers the relevance of trains and other vehicles of mobility for detective fiction, both as a topic of fiction and a place of consumption. On the other hand, it registers that detective fiction has to “travel“ in a more abstract sense before the reading traveler can enjoy it. German publishers appropriated the genre, originally a nineteenth-century American and British invention, at the beginning of the twentieth century. Based on contemporary observations by German cultural critics Walter Benjamin and Siegfried Kracauer, the essay examines German crime-fiction dime novels from the interwar period, compares them to their American predecessors, and analyzes their relationship to mobility and cultural transfer. The text argues that the spatial mobility of the fictional detective is only possible in a specific cultural environment to which the moving but corporeally immobile reader has to be transferred imaginatively.