Before pursuing my stroll, I stepped to the brink, and mechanically looked down, from the point from which I had first seen [the signalman]. I cannot describe the thrill that seized upon me, when, close at the mouth of the tunnel, I saw the appearance of a man, with his left sleeve across his eyes, passionately waving his right arm. (50)
Those who have read "The Signalman" will recognize the gestures as that of the ghost which the signalman described to the wanderer. This was perhaps the most chilling example of foreshadowing in the story, and possibly even symbolism - that of the admonishing specter. Unfortunately, I must leave you at that cliffhanger, lest the conclusion be ruined!
Dickens, Charles. "The Signalman." The Haunted Looking Glass. Ed. Edward Gorey. New York: The New York Review of Books, 1959. 50. Print.