. The Street railway journal . ill enable the run to be accomplished in the specified time. Stop-ping from 20 miles per hour in twenty seconds was adopted as thenegative acceleration in all cases, and positive accelerations , .974, .73, .584, .487, and .417 ft. per second per second werealso adopted, corresponding to starting from rest and attainingspeeds of 20 miles per hour in 20, 30, 40, 50, 60, and 70 seconds, re-spectively. A line was drawn parallel to the abscissae from eachof the above acceleration lines (if they may be so called), enclosingthe same area in each case; this gave th
. The Street railway journal . ill enable the run to be accomplished in the specified time. Stop-ping from 20 miles per hour in twenty seconds was adopted as thenegative acceleration in all cases, and positive accelerations , .974, .73, .584, .487, and .417 ft. per second per second werealso adopted, corresponding to starting from rest and attainingspeeds of 20 miles per hour in 20, 30, 40, 50, 60, and 70 seconds, re-spectively. A line was drawn parallel to the abscissae from eachof the above acceleration lines (if they may be so called), enclosingthe same area in each case; this gave the speed at which the trainmust run, after attaining its acceleration, until the brakes are ap-plied. With a uniform acceleration of ft. per second per secondduring the starting period, we see from Fig. 10 that the speed dur-ing the running was miles per hour until the brakes are ap-plied. The next speed curve, with its acceleration of .974 ft. persecond per second during the starting period, requires a speed of 3000. FIG. 10.—DIAGRAM OF ACCELERATIONS AND TRACTIVEFORCES average of six sets of observations gave lbs. per ton, at per hour, that on the level straight road being lbs., leav-ing lbs. due to the curve. It is, perhaps, worth mentioning that there is a guard-rail oneach of these curves, which, although in good condition and verysmooth, no doubt adds to the resistance. ACCELERATION After an extended consideration of electric locomotive design,the writer takes up the question of acceleration and speed. On thishe says: From practice it appears that to run a level section 2700 ft. long,130 seconds is a convenient time to meet ordinary traffic require-ments. Given this basis, the lowest speed at which it is possible torun the section is miles per hour, assuming infinitely quickpositive and negative acceleration; or, in other words, entering thesection at full speed and running through without stopping. Thisis, of course, an impossibl
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectstreetr, bookyear1884
