The narrator describes the Signal-man's box as supernaturally eerie and desolate:
So little sunlight ever found its way to this spot, that it had an earthy deadly smell; and so much cold wind rushed through it, that it struck chill to me, as if I had left the natural world.
The “deadly smell” and “chill” enhance the unnatural atmosphere, and the box’s location at the bottom of a deep ravine evokes an almost hellish landscape, punctuated by the red danger light. This description lends a suspenseful and dread-laden atmosphere to what otherwise may have seemed like a normal conversation between a traveler and a railway signaler.
The monstrous thought came into my mind as I perused the fixed eyes and the saturnine face, that this was a spirit, not a man. I have speculated since, whether there may have been infection in his mind.
The Signal-man appears like an apparition, or ghost, to the narrator. His “saturnine” visage projects gloom, and his eyes are constantly seeking out specters that only he can see. He is a fitting resident for the eerie and unnatural landscape he occupies. His odd behavior leads the narrator to wonder if he might have an “infection in his mind,” a common nineteenth-century euphemism for madness.
He had been, when young (if I could believe it, sitting in that hut; he scarcely could), a student of natural philosophy, and had attended lectures; but he had run wild, misused his opportunities, gone down, and never risen again. He had no complaint to offer about that. He had made his bed and he lay upon it. It was far too late to make another.
The Signal-man is portrayed as having fallen in station to the point that he now resides in an environment that resembles hell. His isolation and the spectres that appear only to him can be read as a commentary on the increasingly unnatural effects of technology on human nature. The fact that it is “far too late” lends a sense of fatalism to both the Signal-man and the story as a whole, foreshadowing the grim ending.
“What is its warning against?” he said, ruminating, with his eyes on the fire, and only by times turning them on me. “What is the danger? Where is the danger? There is danger overhanging somewhere on the Line. Some dreadful calamity will happen. It is not to be doubted this third time, after what has gone before. But surely this is a cruel haunting of me. What can I do?”
The Signal-man has come to associate the apparition with death and disaster. However, his inability to prevent the incidents that the specter...
(The entire section is 665 words.)