Perhaps the first important event in "The Signal-Man" is the encounter between the narrator and the eponymous signalman. Dickens presents this event as strange and ominous, and he does so in large part through his description of the signalman's physical appearance and attitude. For example, the narrator describes the signalman as "a dark sallow man, with a dark beard and rather heavy eyebrows." The repetition of the word "dark" here, in combination with words like "sallow" and "heavy," implies that the signalman is a brooding, haunted figure.
The narrator also describes the signalman's watchful attitude, which he describes as "of such expectation and watchfulness, that I stopped a moment, wondering at it." The description of the signalman is thus curious because we wonder what he might be watching so intently for, and, because of his physical description, we probably suspect that whatever it is that he is watching for is something particularly ominous.
Arguably the most important event in the story is the signalman's first encounter with the mysterious figure who haunts him thereafter. Dickens presents this moment as mysterious and sinister, and he does so in part by describing the reactions of the narrator as he listens to the signalman recalling this encounter. For example, the narrator describes a "disagreeable shudder (which) crept over" him, and he also says that after the story his mouth "was very dry." The narrator seems so affected by the story that even the wind seems, to him, to emit "a long lamenting wail." These descriptions of the narrator's reactions to the signalman's story help to emphasize how sinister the story is.
The signalman's story about the mysterious, haunting figure is also presented as dramatic by Dickens through the use of speech and sentence types. The signalman describes the cries of the mysterious figure, who, he says, called, "Look out! Look out! ... Halloa! Below there! Look out!" The repetition of short, exclamatory sentences implies a tone of desperation and alarm, which in turn implies an ominous, mysterious sense of danger. It is the suspense surrounding the source and nature of this danger which sustains the drama throughout the rest of the story.