Here is a really great phase of railroad energy. We find our way to a gaunt freight-house, to whose door no truck has ever backed, and which is hemmed in by many rows of sidings and of sheds. In this building one of the busiest functions of the whole transportation business goes forth by day and by night. You ship a box--sixty pounds to one hundred pounds--from Wilkes-Barre, Pa., to Berlin, Wis. Here comes another box from Watertown, N. Y., to Norfolk, Va. A third is bound from Easthampton, Mass., to Chillicothe, O.; a fourth from Terre Haute, Ind., to Plainfield, N. J., and so on, _ad infinitum_. You can readily see how in such cases the railroads have a problem in freight that closely approximates that of the Government mail service. Ten thousand currents and cross-currents of merchandise rising here and there and everywhere, and crossing and recrossing on their way to destination, make a puzzle that does not cease when the rate-sheet experts have finished their difficult work. If all the freight might be expressed in even multiples of cars the problem would not be quite so appalling. But your box is a hundred pounds weight, or less, perhaps--"LCL" anyway. From its destination it goes with other boxes in a car to the nearest transfer point. At the transfer house the car in which it is placed is drilled quickly into an infreight track, seals are broken, doors opened, and re-assorting begins. The transfer-house is roomy and systematic. If it were anything less it would resemble chaos. But the chief freight points of that particular system and its connecting points have regular stands, upon which nightly are placed cars bound for these points. Each city (in the case of a large city each freight-house), each transfer point, has a number, and its through car stands opposite that number. When the infreight arrives and is unloaded piece by piece, a checker, who is nothing less than an animated guide-book, gives each its proper number, and it is promptly trucked off to the waiting car. It is mail-sorting on a Titanic scale. Nor is this an absolute order. Certain towns demand an occasional through car from time to time, and a car must be assigned number and place at the transfer-house against such emergencies. Sometimes there is more than enough freight to fill the car allotted to any given point, and then one of the switching crews must drill that out and find another empty to replace it. Beyond that, the yardmaster's superiors are all the time demanding that he show judgment in picking the cars to be filled. When a freight car gets off the system to which it belongs it collects forfeits from the other lines over which it passes, if they do not expedite its passage; this the railroaders know as "_per diem_." The great trick in operating is to keep _per diem_ down; and so the "foreign" cars, so called, must be promptly returned to their home roads.