Great Dungeon (Metaphor)
Early in the story, the narrator refers to the train tunnel at the entrance to which the signalman works as "this great dungeon." In this metaphor, the narrator compares the empty, abyss-like tunnel to a fortified subterranean prison cell in order to convey the tunnel's nefarious qualities.
Made His Bed (Metaphor)
After the signalman explains how he had abandoned his previous academic ambitions, the narrator comments on how the man was resigned to his life as it was. Instead of stating this directly, the narrator uses a metaphorical phrase: "He had made his bed, and he lay upon it. It was far too late to make another."
Frozen Finger (Metaphor)
As the narrator listens to the signalman discuss his brushes with the specter, he "resist[s] the slow touch of a frozen finger tracing out [his] spine." In this metaphor, the narrator emphasizes the cold creeping sensation running down his back by describing it metaphorically as a frozen finger literally touching his skin.
