On him depends the safety and the comfort of the passengers to a large degree; he must nurse his engine to produce the greatest speed at the least cost of coal, and he must round the curves, climb the grades, and make the slow-downs and stops so gradually that the passengers will not be disturbed.

When a station was reached, when a "caution" signal was displayed, or whenever any one of the hundred or more things occurred that might require a stop or a slow-down, the engineer closed down the throttle and very gradually opened the air-brake valve that admitted compressed air to the brake-cylinders, not only on the locomotive but on all the cars.