good condition, to be placed together, catch; they lodged on the cupola step in ahead of the middle of the air-braked train; there's that chart in the air car showing tests made at Purdue University, of cutting out brakes at different points in a fifty car train; 'bout a hundred tests; shows that three cars can be cut out any old where, and it won't flag quick action; it'll jump more, the further back in the train they are. We got eight more cars on the head end, at Lansing; the sixth, seventh and eighth are cut out-triples robbed of their brass in'ards; that puts five good brakes between 'em and the battle-ship. We'll get flagged down in the bottoms-unloadin' a rail or two at each mile post; we got orders to look out for 'em, but that don't cut any -Si knows we are air to the caboose, and d'rec'ly you'll feel what the 'canary bird' calls a fine 'serial application,' and Tim put his feet up on the cushions. a shower of broken glass from the cupola window through which some of the hind man had gone. The coffee was hot; so was Grogan-"Flaggin' on the caboose steps and we're into 'em, etc." Our engineer had been flagged on a curve and had given her the emergency, but quick action had ceased not far back from the engine. The shock was severe, but luckily, the little damage done was soon repaired except as to the conductor. "Timothy, one of yer goo-goos are the shade of the German colors," observed White Line, "and the keer ahead or the keer behind them three what has their appendixes gone, are got a stopped up triple-valve strainer and won't let 'er go to quick action; and that makes four of a kind, Timothy. You thought you had threes beat-but this yere train had a draw comin' and filled. The gents whose orders you disregarded, knows the air brake game better'n you and me, pard." Presently I heard an ominous sound, like a pneumatic hammer working on a boiler rivet, multiplied many fold; I knew what was coming and braced myself. Not so with Grogan-his hearing is decidedly bad, and when the crash came, the coffee pot, chair and Grogan made a move that the vitascope couldn't cut. George was right; a strainer was found almost full of dirt and scale. It was found and cleaned right there, and in the future Grogan will "pair" them when The Duplex Air Gauge By J. P. Kelly HAT the steam gauge is to the W boiler of the locomotive, the du plex air gauge is to the air brake system, and if comparison of the usefulness of these necessary attachments to the locomotive were to be made, I am inclined to think that the air gauge would be considered, if anything, a trifle more important than the steam gauge. I have known instances in which the steam gauge was dispensed with for several trips. I do not recall a single instance in which it was ever attempted to operate an automatic air brake without the use of an air gauge, except, perhaps it was to complete a trip during which accident to the gauge or its connections rendered it inoperative. It is surprising how much confidence we have in pressure gauges on the engine. Day after day we come around to go out on our trip, and about the first thing we do when we get onto the engine is to glance at the steam gauge to see how much pressure there is on the boiler. We rarely ever question the accuracy of the steam gauge, but generally accept its indications as correct. And we generally do the same by the air gauge; but an incorrect indication on the part of the air gauge is not so readily detected, or, rather, not so closely guarded against as the same defect in the steam gauge. How many of us who use pressure gauges ever inquire about, or take the pains to study up, the workings of these gauges? Judging from experience, I am of the opinion that there are not many of us who do. I thought, therefore, that an explanation of the operation of the air gauge might not be out of place, while we are investigating the subject of air brakes. In the sketches Fig. 6 shows the face of the gauge and the two indicators or hands, one of which is colored black for the train pipe pressure, and one colored and levers 3, and are free to move a limited distance in the direction indicated by the small arrows on the top. The duplex gauge is really two pressure gauges in one case. There are two spindles in the gauge which carry the hands, one made hollow so that the other may pass through, and rotate inside of it. The arrangement of the spindles is the same as that of ordinary clock hands. B As the spindles rotate the hands turn on the face of the gauge, and the distance through which they move is proportional to the distance through which the ends of the ellipitical tubes by means of the levers and link, pull the sector, which, of course, is proportional to the pressure within the tubes. In Fig. 8 we have a view a showing the shape of the tube when there is no pressure except atmospheric pressure in On these spindles, and attached rigidly it, and in the same figure a view b in gins to impart motion to the sector, the the-way, inaccessible spot in the cab latter will immediately impart motion is the one in which the air gauge is to the pinion and to the spindle, thus pre- placed, where it can be seen only with venting the gauge from incorrectly regis- difficulty by the engine crew and, sometering the pressure on account of any times, only when the engineman climbs lost motion due to wear. up into some particular place in the cab to get a view of it. Air gauges as a rule are subject to very hard usage, both from sudden and violent fluctuations in the air pressure within the tubes and from the influence of heat from the boiler. They should be tested occasionally and compared with some standard test gauge to know that they are correct, and then the pump governor should be adjusted to conform to the standard pressures as indicated by the gauge. Adjusting the governor according to the pressures indicated on the gauge without first testing the latter might lead to an increase of pressure in the train pipe that would be sufficient to cause wheel sliding; or it could happen that less than the proper pressure would be carried, and the brakes, in consequence, would not hold so well as they should. Location of Gauge.-Next in importance to having an air gauge in good working order is to have it properly located on the engine. On many locomotives the most out-of When the air gauge is placed in such remote places in the cab it is not reasonable to expect that the engineer can teil exactly to a pound how much air he is drawing off in applying the brakes, or that if the pump should stop from any cause without his knowledge he would detect the pressure falling unless it should reduce fast enough to cause the brakes to drag. The air gauge should be so located that it can be read easily by the engineer when he is operating the brake valve, and should be in easy view of the engine crew at all times. At night it should be lighted just as the steam gauge is, so that at no time will the hands on it be invisible. Roads that practice locating the gauge in the cab in a place to be read conveniently by the engineer find that it pays, as much better work in handling brakes is made possible and there is also much greater freedom from likelihood of accident due to pressure falling gradually below the safe limit. About Westinghouse Brakes Answers by F. B. Farmer 91. Time Required to Charge Auxiliary Reservoir. "About how much time does it take to charge one auxiliary reservoir to 70 pounds with a train pipe pressure of 70 pounds?"-J. S. Answer.-The Master Car Builders' code of tests for triple valves requires that, with the auxiliary reservoir empty at the start, a train pipe pressure of 90 pounds suddenly admitted to and maintained at the triple valve shall not charge the auxiliary to 70 pounds in less than 45 seconds, nor require over 60 seconds. Where the train pipe pressure is raised only to 70 pounds a longer time would be required. Just how much longer would depend largely on the condition of the feed groove. Assuming that the answer desired is one that can be applied in practice, would say that under the conditions named at least one and one-half minutes should be allowed. The condition of many feed grooves is such, through ac cumulated gum, that even this time would be insufficient for complete equalization. 92. Engine Oil or Kerosene in Pump Air Cylinder. "What harm is there in using engine oil or kerosene in the air cyliuder of the air pump?"-O. R. S. Answer.-Compressing the air heats it so much that either engine oil or kerosene will be turned into gas and where the pump is worked hard the oils will burn. This will cause the pump to heat more, run dry and is liable to result in an explosion of the heated gas, particularly with kerosene. On railways valve oil is usually the only one obtainable which will stand the temperature that ordinarily results and even it will soon burn out where a pump with a bad order air cylinder is run fast for a considerable time and working against the ordinary main reservoir pressures. it 93. Releasing Brakes. "Why is harder to release brakes after an emergency application than it is after a service application?"-J. S. Answer. Because an emergency application leaves a higher auxiliary pressure and a lower train pipe pressure than does even a full service application. Release is brought about, where made from the engine, by raising the train pipe pressure above that remaining in the auxiliary reservoirs. Therefore, the greater the difference between these two pressures, the more difficult it is to release the brakes. The use of emergency almost always reduces the train pipe pressure lower than is necessary to fully apply the brakes, but this cannot be helped, as in emergencies the thing of importance is to absolutely insure that all brakes will be applied as quickly and as heavily as possible. 94. Difference in Size of Train Pipe on Engine and Freight Car.—“Please explain why one and one-quarter-inch train pipe is used on freight cars and one-inch on engines."-J. M. R. Answer.-There is no reason why one and one-quarter inch pipe should not be used for the train pipe from the pilot to the rear of the tender, and a number of roads are now doing this so as to allow the air to flow more freely. While the gain in this cannot be very much, the size of pipe mentioned will permit of the use of a quick action triple on the tender at any time desired. 95. Why Use Plain Triple on Tender?"Why is the plain triple used on the tender instead of a quick action valve as on cars.?"-J. M. R. Answer. In the early days of the quick action valve when there were few equalizing discharge brake valves and those had were often in very poor condition the use of the quick action triple on the tender would have resulted in more trouble from undesired quick action than was experienced-and there was enough. Present conditions are so different that there is now no very good reason why the quick action triple should not be used on tenders. In fact, it has for some years been so employed where engines are fitted with the high speed brake. Its satisfactory use requires that the brake valve be kept in good condition, but this is more in its favor than against it. The use of the quick action triple on the tender permits of employing a maximum brake force equal to the light weight of the tender without as great liability of slid flat wheels as would exist where with the plain triple the maximum brake force was but 90 per cent of the light weight. This is because quick action would seldom be required; when it was the chances are that usually there would be considerable coal and water to aid in preventing wheel sliding and in the full service application the tender would be braked at but 83 per cent of its light weight, as against the 90 per cent in either full service or emergency with the plain triple. 96. Air Signal Blows When Brakes are Released. "If signal whistle blows every time brakes are released what is the trouble?"-J. S. Answer. The reducing valve has allowed the signal line pressure to become equal with that in the main reservoir and when the release of brakes causes a fall in main reservoir pressure the pressure flows into the latter from the signal line, causing the reduction which results in the signal whistle blowing. Clean the signal reducing valve, adjust it to regulate the signal line pressure at 40 pounds and the trouble will be overcome. 97. Air Signal Fails With Long Train."Signal system operates all right when coupled to short train, but when more cars are put on signals can not be given from rear car. What is the cause?"J. S. Answer. The usual cause of this trouble is in the signal valve and is too loose a fit of the diaphragm valve stem at the point where it enters the bush below the diaphragm. A baggy diaphragm will aid in causing the trouble asked about and one slightly leaky can alone cause it. |