seat. Thus a partially open port would permit the brake cylinder pressure to rather gradually escape to the atmosphere. As the pressure on top of the piston reduced, the compressed regulating spring would lengthen out, the piston and slide valve be forced upward until finally the ports would be closed as was the case in the preceding example of the service application. Q.-517. At the instant the slide valve and piston reached their lower traverse, brake cylinder pressure began to escape to the atmosphere through the smallest opening made by the triangular port. As the pressure gradually reduced, the piston and slide valve came upward, making the small port larger at each instant, until just before closing, the port was wide open. Has this action any significance? A. Yes. At the moment the emergency application was made, presumably at highest speed, the brake cylinder was the highest, and reduced the slowest. Thus the greatest pressure was had and held when it was needed most. As the speed reduced, the variable port opening became larger and finally, after reaching its largest opening, closed entirely. Thus the variable braking pressure was fitted to the variable speed. Q.-518. Does the speed of the train actually regulate the closure of the passageway in the slide valve and its seat? A.-No. The size and form of the ports are designed to accomplish the desired result. Q.-519. Was there not an early attempt to regulate the brake pressure by some such means? A. Yes; but owing to the complicated and sensitive apparatus required, the attempt proved unsuccessful and was abandoned. The present plan has proved to be positive and reliable. Q.-520. Is the high speed brake generally used? A. Yes. It was first introduced several years ago on the fast express trains of the New York Central, Pennsylvania and Lehigh Valley roads. Later it grew into more general use on nearly all the leading railway lines. Q.-521. Has it given good service and come up to expectations? A. Yes, doubly so. Besides making high speeds safe, it has created an exceptional record of never having had a flat wheel reported-and this, too, while exerting a maximum braking force equal to 125 per cent. of the weight of the car braked. Q.-522. Suppose a car not fitted with the automatic reducing valve should be placed in a high speed braked train. Would not the wheels under that car be flatted? A.-When ordinary cars are thus temporarily used, a small safety valve is screwed into the oil plug hole of the brake cylinder as shown in Fig. 47. Q.-523. Fig. 48 shows a duplex governor and two feed valves. What are these for? A. By turning the handle of the reversing cock, the engine equipment may be quickly suited to either a high speed train or an ordinary train. SCHEDULE U OR HIGH PRESSURE CONTROL. Q.-524. What is the "Schedule U" or "High Pressure Control Apparatus?" A. It consists of a duplex device designed to meet the needs of special airbrake service, where the pressures ordinarily employed may be quickly changed to higher pressures to meet more difficult conditions, such as controlling trains of heavily loaded cars down steep grades. Q.-525. For what class of service is this device particularly designed? A. For coal, iron and other mineral carrying roads in mountainous districts, where loads are carried down hill and empties hauled up. Thus it will be seen that the usual pressure may be employed on the light train up the grade where little braking power is demanded or needed, and by merely reversing a cock, the apparatus may be changed to give a predetermined higher pressure with which to operate the loaded train down the grade. Q.-526. Then the apparatus may be quickly changed to meet the needs of a loaded or empty train. Could not this device be advantageously used in ordinary service where a portion of the road is mountainous and a part level? A. Yes. It is rapidly being adapted to that service and others where circumstances require it. Q.-527. Of what does the Schedule U or High Pressure Control device consist? A.-It consists principally of a duplex governor, two feed valves properly protected from heat and cold and suitable connections as illustrated by the accom FIG. 58. DIAGRAMMATIC SKETCH OF THE WESTINGHOUSE SCHEDULE U, OR HIGH PRESSURE CONTROL APPARATUS. panying cut. (Fig. 58.) As will be recognized, the device is merely a modification of and an attachment to the ordinary engine equipment. Q.-528. Describe the operation of the apparatus. A.-The two pump governor heads are adjusted for 90 and 110 pounds respectively. Likewise, the two feed valve attachments are set for 70 and 90 pounds. To operate the low or ordinary pressure feature, the handle of the reversing cock is turned to the left, as shown in the diagram. This cuts out the 110 pound governor and 90 pound feed valve, and renders operative the 90 pound governor and the 70 pound feed valve. Thus the high pressure control parts are cut out and the low pressure cut in. By reversing the position of the reversing cock handle, the low pressure parts are cut out and the high pressure parts cut in. Q.-529. Then there are really two complete pump governors and feed valve attachments-one for the ordinary or low pressure and one for the high pressure? A. Yes. With the reversing cock turned to the left, we have 90 pounds in the main reservoir, and 70 in the train pipe and auxiliary reservoirs. With the handle to the right and the small cock in the 90 pound governor pipe closed, we get 110 pounds in the main reservoir, and 90 in the train pipe and auxiliary reservoirs. Q.-530. Why is the pipe to the 90 pound governor not connected to the main reservoir pressure in the brake valve as the 110 pound governor pipe is? A.-The 90 pound governor pipe is connected to the chamber in the feed valve bracket which communicates with the upper chamber of the 70 pound feed valve, thus giving 90 pounds in the main reservoir when the brake valve handle is in full release and running positions, but allowing the pump to keep on working until stopped by the 110 pound governor when the brake valve is on lap. Q.-531. Would not the high pressure permitted by the 110 pound governor and 90 pound feed valve tend to loosen driving wheel tires by excessive heating and slide wheels under a tender partly relieved of its coal and water? A.-No, as safety valves are supplied for the driver and tender brakes to limit the pressure there to 50 pounds. On very long and heavy grades, it is generally desirable to cut out the driver brakes and use the water brake on the engine to assist the tender and train brakes. Q.-532. If the reversing cock should leak, what would happen? A.-A leakage or mingling of pressures would follow and interfere with the proper operation of the device. This part should be looked after with the same care given the other parts in ordinary service. [TO BE CONTINUED.] A Railroad Wreck. BY CLEO M'CANN-AGE 14. "Many years ago when I was railroading in the west," said old John Lane, I was a witness to one of the most terrible wrecks that ever occurred in Arizona, and saw one of the most trustworthy men that ever pulled the bell cord on a train." "Tell us the story," said the crowd of men and boys who had gathered round the old engineer. "Well, I will tell it to you as I remember it if you wish to hear it. "It has been years ago, but I remember it as well as if it happened yesterday. "I was running on the C. & T. My engine was called Big Sal. The road was rough and there was a bridge over Cross Creek that was unsafe. Harvey Ross was the conductor on our train. We received our orders and left Dalton fifteen minutes late. The run was a long one and Conductor Ross said: "John, it is smooth running after we leave Dover, so we can make up some of our time.' "The train was a heavy one, being a picnic excursion bound for Vine Grove, a small station ten miles from Cross Creek. "The children were laughing merrily, the women were gathered together in groups, chatting gaily, and the men were enjoying a quiet smoke in the smoker. "It was a beautiful sunny day in early summer, everybody and everything seemed to be injoying themselves and no one thought of the danger they were in. "At last we neared Cross Creek and all seemed to be right; but when we came to the center of the bridge it creaked and in an instant the cars were thrown into the water, which, fortunately, was very low. The children, men and women who only an hour ago had been so happy, were now lying mangled and dead. All was confusion. The piteous wail of women and the deep sobs of the men brought tears to the eyes of those who were uninjured. My God, can I ever forget the sight," and the old man brushed his coat sleeve across his eyes. "Harvey Ross's wife and child were on the ill-fated train. They were severely injured. After arranging them as comfortably as possible, he started to help the other wounded and dying who were trying to crawl from under the debris. Yard at Chicago. own engines, the remaining half being transferred by the belt lines. The greatest center of freight traffic in the world is found at Chicago, the meeting place of the eastern and western trunk lines. Here, every day of the year, there are handled about 10,000 cars of freight. Of this number over sixty per cent are cars loaded with through freight or cars which have entered the city by one railroad and will have to leave it by some other road. To transfer these 6,000 cars will mean, in the case of many of them, that they will have to be hauled over fifteen miles from the incoming yard of one road to the outgoing yard of another, and that there will be a delay of a whole day in making the transfer. The other 4,000 cars are loaded with freight for Chicago. Under the system which has hitherto been followed in the transfer of this traffic, the trunk lines enter a terminal yard of the company, in which the freight trains are broken up, the cars sorted according to their destination, and outgoing trains made up. The inbound cars destined for an outgoing journey by other roads are taken by switch engines to the yards of these roads, or else they are distributed by means of belt lines which have been built especially to connect the terminal yards of the various railroads. Over half of the cars are transferred by the various roads themselves with their *Courtesy Scientific American. Page 70, Feb. 1, 1902 It can be understood that this work of transfer involves much delay and labor, and it may often happen that a through car, reaching the yard shortly after the transfer train has left, will be delayed several hours before it can start out for the other road, or if the freight is specially important, a special trip has to be made for it. There are twenty trunk lines entering Chicago, and altogether the various belt lines and connecting lines have to operate a total of twentyseven different yards. The distance between the yards varies from a tenth of a mile up to sixteen miles, and it is estimated that the total number of cars interchanged daily averages over 7,000, while to haul them calls for the work of 264 engine round-trips. With these figures before him, the reader can readily understand that this system of independent operation of the yards causes endless complications and delays, involving in the aggregate a considerable expense to the railroads. The system which we illustrate in the accompanying engravings has been designed by A. W. Swanitz, C. E. for the Chicago Union Transfer Railway Company, for the purpose of overcoming the difficulties inherent in the present system of transfer and |