Through yards such as these there are incoming streams of merchandise, equal at least to the outgoing, passing through classification yards in carload lots and the great transfer-houses in "LCL." These streams must be kept separate and from clogging one another or themselves. Cars must carry loads whenever they are moved--"empties" are the bogy-men of the superintendents of transportation--and cars from "foreign" systems must be quickly returned to their home roads. The yardmaster at a busy freight point has his own worries. His puzzle is unending. To it he must bend the bigness of a big mind, he must be prepared to handle the unequal volumes of traffic that pass through his domain with an equal skill: in dull times he must seek to keep his plant working under conditions of rare economy; when the freight rises to flood tide, he must fight in harness to prevent the freight from congesting. The word "failure" has been stricken out of his vocabulary by his superiors. It takes a high grade of railroader to serve as yardmaster. CHAPTER VIII THE LOCOMOTIVES AND THE CARS HONOR REQUIRED IN THE BUILDING OF A LOCOMOTIVE--SOME OF THE EARLY LOCOMOTIVES--SOME NOTABLE LOCOMOTIVE-BUILDERS--INCREASE OF THE SIZE OF ENGINES--STEPHENSON'S AIR-BRAKE--THE WORKSHOPS--THE VARIOUS PARTS OF THE ENGINE--CARS OF THE OLD-TIME--IMPROVEMENTS BY WINANS AND OTHERS--STEEL CARS FOR FREIGHT. From out of the fiery womb of steel comes the locomotive. We have already told of the honor that is forged in the building of the bridge; honor of no less degree has gone into the forging of the most vital and most human thing upon the railroad, outside of man himself. That man has ever been able to create and build the locomotive, a giant creature of some 200 tons, perhaps, built together with infinite care of some 5,000 to 7,000 parts, and these parts acting with the delicacy of the hair-spring of a watch, almost passes ordinary belief. The wonder becomes even greater when it is realized that this monster creature, set upon two slender rails, is capable of pulling a 4,000 ton train, through every stress of weather and over considerable grades. To tell in detail of the locomotive in one chapter is short allowance to a subject that fairly demands for itself a whole book, a technical mind for the telling, and at least a fairly technical mind for the understanding; a subject that in its history goes hand in hand with that of the railroad itself. Yet the limitations of this book forbid a more lengthy description.