A passenger train, No. 1, leaving A at 12 midnight and arriving at N at 4.05 A.M. A fast express, No. 2, leaving N at 12.45 and arriving at A at 3.30. A local passenger train, No. 4, which leaves N at 1.15, runs to E by 4 A.M., stops there until 4.10, and returns to N by 7 A.M.; being called No. 3 on the return, as the direction is always indicated by the train-number's being odd or even. No. 5 is a way freight, leaving A at 12.05 and making long stops at each station. No. 6 is an opposing train of the same character.
Diagram Used in Making Railway Time-Tables.
A lamp swung across the track is the signal to stop.
The diagram shows at a glance how, when, and where all these trains meet and pass each other, and where every train is at any moment. Should it be desired to send an extra train at any time, a line drawn or a string stretched on the board will indicate what opposing trains must be guarded against. For instance, to send an extra through in three hours, leaving A between 1 and 2 A.M., a trial line will show that Nos. 5, 2, 4, and 6 must all be met or passed, and as (on a single-track road) this can only be done at stations, the extra must leave at 1.35 A.M., pass No. 5 at E, meet No. 2 at F, No. 4 at I, and No. 6 at J. A dotted line on the diagram indicates its run, and that No. 2 is held at F for 5 minutes to let it pass. If the road is double-tracked, only trains going in the same direction need be regarded.[16]
A lamp raised and lowered vertically is
the signal to move ahead.
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.