With the "O. K." of the car inspectors finally pronounced, the train that was comes up to the hump, and the expert crew that operates there makes short work of sorting out the cars--this track for "stuff" southwest of Pittsburgh, this next for Cleveland and Chicago, the third for transcontinental; and so it goes. Two lines of cars are drilled at the same time, for just ahead of the switch-engine is an open-platform car, known as the "pole-car," and by means of heavy timbers the "pole-man" guides two rows of heavy cars down the slight grades to their resting-places. The cars do not rest long upon the classification-yard tracks. From the far end of each of these they are being gathered in solid trains, one for Pittsburgh, another for Cleveland and Chicago, the third transcontinental, and so on. Engines of the next division are being hitched to them, pet "hacks" brought from the caboose tracks, and the long strings of loaded box-cars are off toward the West in incredibly short time. Of course there are some trains that never go upon the "classification" at Randall's yard. There are solid coal trains bound in and out of New York, of Philadelphia, and of Boston, that pass him empty and filled, and only change engines and cabooses at his command. There are through freights, bound from one seaboard to the other, from the Far East to the Far West, that do likewise. But the majority of the freight movement has the sorting out within his domain, his four humps are busy day and night with an ordinary run of traffic, and you shudder to think what must be the condition when business begins to run at high tide. "We get it a-humming every once in a while," he finally confesses. "We had one day, a little time ago, when we received 121 east-bound trains in twenty-four hours, more than 3,200 cars all told. That meant, on an average, a train every 11-1/2 minutes. That same day we got 78 west-bound freights, with more than 3,600 cars. That meant nearly 7,000 cars handled on the in-freight in twenty-four hours, or a train coming in to me every 7-1/2 minutes during day and night. They don't do much better than that on some of the subway and elevated railroads in the big cities; and I haven't said a word about the trains and cars we despatched--just about as much again, of course."