"Halloa! Below there!"
The story begins with this line of greeting when the narrator tries to catch the signalman's attention, and the phrase is repeated several times throughout the story. The signalman is visibly perturbed by the combination of words, and he asks the narrator if the words were conveyed to him from a supernatural force. The signalman later explains that these are the exact words the apparition has been calling to him. At the end of the story, the train driver who kills the signalman reports that he also spoke these words just before he ran the signalman over.
"His pain of mind was most pitiable to see. It was the mental torture of a conscientious man, oppressed beyond endurance by an unintelligible responsibility involving life."
In this passage, the narrator comments on how the signalman's dilemma is made visible through the man's evident stress. He knows a disaster is coming, but the lack of details about the crash means he doesn't know how to warn others without appearing to have lost his mind. The narrator sees how the weight of this invisible responsibility is crushing the signalman, and this sympathy leads him to take responsibility for the signalman later in the story.
"A mere poor signalman on this solitary station! Why not go to someone with the credit to be believed and the power to act?"
In this passage, the signalman laments the injustice of his position. He wonders why the specter goes to him when he has so little power to effect change. He wishes the specter would bring its message of danger to someone who has the power to avert the coming disaster. In hindsight, the signalman's statement is ironic: once the reader learns that the specter was trying to warn the signalman of his own death, we see how the specter went to the only person who had the power to avert the disaster.
"He had made his bed, and he lay upon it. It was far too late to make another."
After the signalman tells the narrator of how he is overeducated for the job he has, he comments on how he is resigned to his life as it is. Using metaphoric language, the narrator summarizes the signalman's attitude. The "bed" he has made is his life; it is suggested that he is too old now to go back and make a new life for himself, so he may as well get comfortable with the life he has.
"Just then there came a vague vibration in the earth and air, quickly changing into a violent pulsation, and an oncoming rush that caused me to start back, as though it had the force to draw me down."
In this passage, the narrator uses kinesthetic imagery to show how an oncoming train is first registered as a vibration before it is seen. The narrator's diction, which includes words such as violent, rush, and force, suggest that there is something ominous and terrifying about the train. By focusing on the uneasy feeling the passing train induces in the narrator, Dickens contributes to the story's haunting atmosphere.
"I never left off calling to him. I put this arm before my eyes not to see, and I waved this arm to the last; but it was no use."
At the end of his explanation, the train driver demonstrates for the narrator how he covered his eyes and waved his free arm as he ran down the signalman. His statement presents an instance of situational irony, as the driver's gesticulations match those of the specter's. The narrator is able to conclude that the specter had in fact appeared to warn the signalman of his impending death.
