The dispatcher has, meanwhile, entered the number of the train, the names of conductor and engineer, the number of the engine and the number of cars on the train-sheet, as well as the hour and minute of the train's departure. When it passes the first station, the operator there calls up the dispatcher and reports the hour and minute at which it passed. This also is entered on the sheet, and as the train proceeds, the column of figures devoted to it grows. The record of east-bound trains starts at the top of the sheet and grows downward, while that of west-bound trains starts at the bottom of the sheet and grows upward. It should be remembered that east-bound trains always bear even numbers, and west-bound trains odd numbers. By this method, the dispatcher keeps a record on the sheet before him of the progress of every train. He knows the exact position of every train, or, at least, he knows the last station passed by each, and the probable time of its arrival, barring accident, at the next station. His problem is to keep all the trains moving, to keep a clear track for the passengers so that they can run on time, and to arrange meeting-points for trains going in opposite directions so that there will be no unnecessary delays. It should be understood that, while a few of the larger railroads are double-tracked, the great bulk of the railroad business of this country is done over single-track roads. On these roads, points of meeting or passing must be at sidings, upon which one train can run while the other passes on the main track. Such sidings are usually at stations, and the problem of making the trains meet there is a very delicate one. In order to accomplish this with the least delay, the trains are divided into classes. The east-bound passengers always have the right of way, and expect a clear track. West-bound passengers must make arrangements to get out of the way of east-bound ones, but have precedence over all other trains. Regular freight-trains must make provision to leave the track clear for the passengers, while the extra freights, which have no regular schedule, creep from station to station as best they can, giving all the other trains a clear track--a sort of yellow dog which every one is privileged to kick. All the regular trains, passenger and freight, run by the time-card. That is, each of them has its regular time for reaching and leaving every station on the road, and as long as all the trains are on time, things move smoothly and the dispatcher has an easy time of it. But it is indeed a red-letter day when all trains are on time. So many things may happen, there are so many possible causes of delay, that almost inevitably some of the trains will run behind. It is then that the dispatcher shows the stuff that is in him; if he knows his business thoroughly, he will not only keep the trains moving promptly, but will give those that are behind a chance to make up some of the time which they have lost.