Let it be said here that east-bound trains are always indicated by even numbers and west-bound trains by odd ones. Thus, on any road, “Number Four,” for instance, will always be an east-bound train, and “Number Three” will always be a west-bound one. In addition to which, it should be remembered that east-bound trains always have right of way over west-bound trains of the same class. That is to say, when an east-bound and west-bound first-class passenger train meet, it is the west-bound train which runs in on a siding and waits until the other sweeps by on the main track. “Now,” continued Mr. Schofield, “we’ll begin with Number Four, which has rights over everything. Look at those notes, Allan, and tell me at what time it is to leave Cincinnati.” “At 12.15 P. M.,” said Allan, picking up the note-book. “Correct. Now this line running up and down across the centre of the board is for twelve o’clock noon. This third line after it is for 12.15, five minutes for each line. This line across the top of the board is for Cincinnati, so I drive a pin there and loop the end of this cord around it, so,” and he suited the action to the word. “Now, at what time does Number Four reach Wadsworth?” “At 3.05,” answered Allan, looking at the notes. “Well—see, here is the 3.05 line, and here, running across the board, about midway down, is the Wadsworth line. I drive another pin at the intersection of these two lines, draw the cord tight and loop it about this second pin. And now what?” “The train stops at Wadsworth five minutes to change engines,” said Allan. “So I drive a third pin right out along this Wadsworth line at the intersection of it and the 3.10 o’clock line. Now, what time does it reach Parkersburg?” “At 5.50 P. M.” “Well, here’s the 5.50 line, and here, at the bottom of the board, is the Parkersburg line. I drive a fourth pin there, draw the cord tight and tie it. Then I cut it off, and tie at the end this little tag marked ‘Number Four.’ Now what does that cord indicate?” Allan, looking at the board, saw a line that ran roughly like this: [Illustration: (For complete time-table, see diagram facing page 60)] “Why,” he answered, after a moment, his eyes shining, “the cord indicates the exact time that the train passes every station along the line.” “Exactly,” assented Mr. Schofield. “Now, just by way of illustration, we’ll put on a west-bound train next,” and he picked up the red ball. “We’ll take Number Three. At what time does it leave Parkersburg?” “At 11.40 A. M.” “So I drive the pin here. When does it reach Wadsworth?” “At 2.20 P. M.” “So the pin goes here. It stays there five minutes, doesn’t it?” “Yes—just like Number Four.” “So another pin goes here. When does it reach Cincinnati?” “At 5.35 P. M.” “And here’s the fourth pin—and there’s your red string across the board, indicating Number Three. Now look at them.” Here is what Allan saw: [Illustration: Time-Table]