The Possibilities of Destruction in the Great Speed of a Locomotive--The Energy of Four Hundred Tons Moving at Seventy-five Miles an Hour--A Look ahead from a Locomotive at Night--Passengers Killed and Injured in One Year--Good Discipline the Great Source of Safety--The Part Played by Mechanical Appliances--Hand-brakes on Old Cars--How the Air brake Works--The Electric Brake--Improvements yet to be Made--Engine Driver Brakes--Two Classes of Signals: those which Protect Points of Danger, and those which Keep an Interval between Trains on the Same Track--The Semaphore--Interlocking Signals and Switches--Electric Annunciators to Indicate the Movements--The Block Signal System--Protection for Crossings--Gates and Gongs--How Derailment is Guarded Against--Safety Bolts--Automatic Couplers--The Vestibule as a Safety Appliance--Car Heating and Lighting. In 1829, when Ericsson's little locomotive "Novelty," weighing two and a half tons, ran a short distance at the rate of thirty miles an hour, a writer of the time said that "it was the most wonderful exhibition of human daring and human skill that the world had ever seen." To-day trains weighing four hundred tons thunder by at seventy-five miles an hour, and we hardly note their passage. We take their safety as a matter of course, and seldom think of the tremendous possibilities of destruction stored up in them. But seventy-five miles an hour is one hundred and ten feet a second, and the energy of four hundred tons moving at that rate is nearly twice as great as that of a 2,000-pound shot fired from a 100-ton Armstrong gun. This is the extreme of weight and speed now reached in passenger service, and, indeed, is very rarely attained, and then but for short distances; but sixty miles is a common speed, and a rate of forty or fifty miles is attained daily on almost every railroad in the country. We cannot tell from the time-tables how fast we travel. The schedule times do not indicate the delays that must be made up by spurts between stations. The traveller who is curious to know just how fast he is going, and likes the stimulus of thinking that he is in a little danger, may find amusement in taking the time between mile-posts; and when these are not to be seen, he can often get the speed very accurately by counting the rails passed in a given time. This may be done by listening attentively at an open window or door. The regular clicks of the wheels over the rail-joints can usually soon be singled out from the other noises, and counted. The number of rail-lengths passed in twenty seconds is almost exactly the number of miles run in an hour. [Illustration: Danger Ahead!]