In addition to this constant mental tension the engineer on this hurling train has to endure material discomfort, often bodily suffering. The air sweeps back in his face with the breath of a hurricane, blowing smoke and cinders into his eyes. Most people know the intense pain a cinder causes in a man's eye, particularly a hot cinder. The suffering is almost unbearable, and yet, suffering or no suffering, the engineer who gets a cinder in his eye can have no relief until the end of his relay. They shut their lips, these unflinching men, keep looking ahead, and bear it. Long after they leave the cab, the burning sensation in their eyes and eyelids continues, and even persists after hours of sleep. "It seems as if nothing would rest my eyes, sir," said one of the new men after his first week on the flyer. No wonder the eyesight of engineers fails rapidly, no wonder many of them are removed from their positions every year because the examining doctors find them unable to distinguish the signals. The engineer suffers also from the plunging and tossing of the monster locomotive, which bruises his whole body with its violent rocking, and causes sharp pains in the back, particularly where there is any tendency to kidney trouble. One has only to watch these strong men as they stumble down from their engines at the end of a relay, has only to observe their white faces and unsteady gait, and see the condition of physical collapse which follows, to understand what it costs in vitality and grit to give the ease-loving public this incomparable train service. [Illustration: "THE FLYER" LEAVING THE GRAND CENTRAL STATION, NEW YORK CITY.] Thus it is that while the New Yorker gets to Chicago with scarcely more discomfort than if he had remained at home, the same journey wears out seven engineers, all picked men; for many of them who have seen years of service on trains running forty miles an hour, break down entirely when put upon the flyer. So exhausted are these seven engineers by their comparatively short relays that they are obliged to lay off entirely during the following day to recover from the shock. They do not even take the opposite-bound flyer back over their stretch, but return with their engines to their respective starting-points, drawing slower trains. Thus, seven strong men do two days' work every time the flyer runs from New York to Chicago, and seven other men do two days' work every time it runs back. Each engineer works three hours on the flyer, returns home on an easy train, and then rests forty hours before his muscles and nerves and brain are in condition to repeat the operation.