But the more usual way of handling extra trains, when circumstances will permit, is to let them precede or follow a regular train upon the same schedule. The train is then said to be run in "sections," and a ten minutes' interval is allowed between them. That opposing trains may be informed, the leading section (and when there are more than two all but the last) wears on its locomotive two green flags by day and two green lights by night, indicating that a train follows which is to be considered as a part of the train leading, and having the same rights. [Illustration: A lamp swung vertically in a circle across the track, when the train is standing, is the signal to move back.] So far the rules are very simple, and they would be all that is necessary if all trains could always be kept exactly on time. But as that cannot be, provision must be made for all the complications which will result. The first and most important rule is that no train must ever, under any circumstances, run _ahead_ of time. The next is that any train making a stop not on its schedule must immediately send out flagmen with red flags, lights, and torpedoes to protect it. This rule is a very difficult one to enforce without rigid discipline, and its neglect is the cause of a large percentage of the accidents "that will happen." The flagman who must go to the rear, often a half-mile, at night, across trestles and in storms, must frequently be left behind, to take his chances of getting home by being picked up by a following train. There is no one to watch him, and he will often take chances, and not go as far back or as fast as he should; and if all goes well no one is ever the wiser. [Illustration: A lamp swung vertically in a circle at arm's length across the track, when the train is running, is the signal that the train has parted.] Now, when a train is prevented from arriving on time at its meeting-point, we must have some rules by which the opposing train may proceed, or all business on the road would be suspended by the delay of a single train. Only the general principles of these rules can be stated within limits. They are as follows: 1. All freight trains must wait indefinitely for all passenger trains. 2. When one train only is behind time, the opposing train of the same class will wait for it a specified time, usually ten minutes, and five minutes more for possible variation of watches, then go ahead, keeping fifteen minutes behind its schedule. 3. But should such a train, running on delayed time, lose more time, or in any other way should both trains get behind time, then the one which is bound in a certain direction--for instance, north--has the right to the track, and the other must lie by indefinitely. [Illustration: The General Despatcher.]