. Locomotive engineering : a practical journal of railway motive power and rolling stock . showed even greater dif-ferences between initial and final pres-sures, the increase of pressure due to therise of shoe varying from 10 to 115 percent. In one hand-brake test, two and ahalf times the calculated emergency pres-sure at the air brake was gotten on thebrake shoes. In a similar test the handbrake chain broke. The highest percent-age of increase was obtained by slacking■back the car after it had been first started,and then starting forward again. Thesetests brought increases varying between 93a
. Locomotive engineering : a practical journal of railway motive power and rolling stock . showed even greater dif-ferences between initial and final pres-sures, the increase of pressure due to therise of shoe varying from 10 to 115 percent. In one hand-brake test, two and ahalf times the calculated emergency pres-sure at the air brake was gotten on thebrake shoes. In a similar test the handbrake chain broke. The highest percent-age of increase was obtained by slacking■back the car after it had been first started,and then starting forward again. Thesetests brought increases varying between 93and 115 per cent. These tests prove that greater possibil-ities of wheels sliding exist in yards wherehand or air brakes have been left set thanout on the road where wheels are popu-larly supposed to be ruined; and usefulhints may be taken from them by the air-brake man whose duty it is to run downflat wheels. Testing Worn and Repaired TripleValve Packing Rings. Editor: I was quite interested in the articles ofMessrs. F. B. Farmer and E. W. Prattin your August number. They both agree. that it is good practice to test triple valvesfor defective packing rings, but do notgive sufficient details of the test they findmost satisfactory, to enable others toprofit by their experience. At the Balti-more convention of the Air-Brake Asso-ciation there was some discussion on this paired triple valves are required to releasewhen the pressure in the train line is in-creased through a hole in a diaphragmsuitably arranged. The size of the hole is determined inthe following manner: Under a constanthead of 90 pounds the train line shouldcharge from o to 60 pounds in seven min-utes. While this is not as close a test asis required of triples to pass the M. C. , where I am informed that the pres-sure under a constant head of 90 poundswill, feeding through a 3-32-inch hole, in-crease the pressure in a train line of fiftycars from o to 60 pounds in about tenminutes. The correctness of this la
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectrailroa, bookyear1892
