A train whistle at night was a word that meant the same thing in all languages. It was compounded of loneliness and otherness and the futile desire to be anywhere but here, anybody but one’s own wretched self. What made the heart ache at the sound of it was the knowledge that the locomotive was pulling out without you and always would. You were never going to catch that imaginary train that would carry you to the faraway land containing the solutions to all your problems. You were never going to arrive at the impossible city where all the things for which you secretly yearned were given away free in the streets.
—Michael Swanwick, The Dragons of Babel