. Railway and locomotive engineering : a practical journal of railway motive power and rolling stock . ht air brake valve handle to re-lease position, reapplying later if neces-sary by using the straight air brakevalve in the usual way. Keep both brake valve handles intheir running positions when each is notin actual service. If the straight air brake valve handleis left in release position, it is impos-sible to apply the engine brakes withthe automatic valve. to explain why it was that a reductionof 20 lbs. from an initial brake pipepressure of 110 lbs. did not equalize theauxiliary and the b
. Railway and locomotive engineering : a practical journal of railway motive power and rolling stock . ht air brake valve handle to re-lease position, reapplying later if neces-sary by using the straight air brakevalve in the usual way. Keep both brake valve handles intheir running positions when each is notin actual service. If the straight air brake valve handleis left in release position, it is impos-sible to apply the engine brakes withthe automatic valve. to explain why it was that a reductionof 20 lbs. from an initial brake pipepressure of 110 lbs. did not equalize theauxiliary and the brake cylinder, whilefrom an initial brake pipe pressure gf70 lbs. it will do so, the piston travelbeing the same in both cases. .Mthough we explained the opera-tion of the law mentioned above asclearly as we possibly could, and ourlisteners did not doubt the correctnessof our statement, yet the working ofthe law under special cases producedresults which they could not clearly un-derstood. We must admit that it isnot always easy, by means of word ex-planation, to make clear to others the roK TfiAIN. .MTTOMATIC BR.\KE VALVE. FIG. 1. Engine brakes cannot be releasedwith automatic valve unless thestraight air brake valve handle is inrunning position. It is important that the positions ofthe brake valve handle be carefullystudied, so that it may be handled skil-fully. Equalized Pressures. The law of Boyle and Mariotte statesthat in the expansion, or in the com-pression, of a perfect gas, assuming thatihe temperature remains constant, theproduct of the pressure by the volumeis always constant; or another way ofstating this law, the pressure and thevolume vary inversely. This law, though well understood bymany air brake students, and one thatis in daily use in calculations pertainingto the varying pressure of air, does not,at first sight, appear to account satisfac-torily for some of the observed resultsin practice. Some time ago we were called upon RUVf*JlVG POilTfO/l/
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectrailroa, bookyear1901
