Meantime, what is the engineer of this fastest train in the world doing for the passenger? In the first place, the Chicago flyer is not driven by one but by many engineers. In order to cover the nine hundred and sixty-four miles between the two cities in twenty hours, including nine stops, there are required seven huge engines in relays, driven by seven grimy heroes. A run of less than one hundred and fifty miles is the limit per day for each engine, while three hours of the plunging rush wears out the strongest engineer. Sixty, seventy, eighty miles an hour--what does that mean to the man at the throttle? It means that the six and a half feet drivers turn five times every second and advance one hundred feet. Tic-tic-tic, and the train has run the length of New York's highest steeple. The engineer turns his head for five seconds to look at the gauges, and in that time the terrible iron creature, putting forth the strength of a thousand horses, may have shot past a red signal with its danger warning five hundred feet away. Ten seconds, and one thousand feet are left behind--one-fifth of a mile. Who knows what horrors may lie within that thousand feet! There may be death lurking round a curve, death spreading its arms in a tunnel, and the engineer must see and be responsible for everything. Not only must he note instantly all that is before him, the signals, switches, bridges, the passing trains, and the condition of the rails, but he must act at the same moment, working throttle, air-brakes, or reversing-lever, not as quick as thought, but quicker, for there is no time to think. His muscles must do the right thing automatically under circumstances where a second is an age. In the three hours of his vigil there are ten thousand eight hundred seconds, during each one of which he must watch with the mental alertness of an athlete springing for a flying trapeze from the roof of an amphitheatre, with the courageous self-possession of a matador awaiting the deadly rush of a maddened bull; and far more depends upon the engineer's watching well, because, if he fails by a hair's breadth in coolness or precision of judgment, there may come destruction, not only to himself, but to hundreds of passengers, who, while he stands guard, are perhaps grumbling at the waiters in the dining-car or telling funny stories in the smoker.