. A study of the various experiments for the determination of the resistance of electric cars and trains . y the rubbing of the Journals on the sides of thebearings and has been assumed to be practically constant byall investigators up to the present time. With good lubrica-tion it is a very small part of the total resistance,especia-ly at high speeds. The frictional resistance of gears andmotor commutators must be considered in dealing with gearedmotor cars. ,after s study of the laws of frictioninvolved,has decided that this component is small at lowspeeds but increases appreciably
. A study of the various experiments for the determination of the resistance of electric cars and trains . y the rubbing of the Journals on the sides of thebearings and has been assumed to be practically constant byall investigators up to the present time. With good lubrica-tion it is a very small part of the total resistance,especia-ly at high speeds. The frictional resistance of gears andmotor commutators must be considered in dealing with gearedmotor cars. ,after s study of the laws of frictioninvolved,has decided that this component is small at lowspeeds but increases appreciably with the speed. John Lundie*in his tests on the South Side Elevated Railway of Chicagoneglected this component. Therefore his formula gives toohigh results for trains composed of trailing cars drawn bylocomotives. The general attitude of most investigators towards trackresistance,is summarized in an editorial in the Street Rail-way Journal of August 4,1900,in which the total track resis-tance is divided as follows; pure rolling friction,which issmall and fairly steady; joint friction,which consists of. EUGENE DIETZGEN CHICAGO. 3. the resistance due to the irregularities of rail joints,ratherlarge and variable; flange friction due to rocking and jarringof trucks and to wind,large and exceedingly irregular; andfinally the work against gravity due to the irregularities andflexure of track,very variable and at times very large. Thebearing and rolling resistance of wheels on the track,togetherconstitute the principal component of train resistance at lowspeeds,and may be considered to remain fairly constant irresp-ective of the speed. The flange and gravity components evident-ly depend on the condition of the track and the swaying of thetrain,and therefore on the speed. Their value at very lowspeeds can be considered negligible but at moderate and highspeeds,they are of more or less indeterminate importance. The air resistance can be divided into head pressure,rear suction,and s
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Keywords: ., bookcentury1900, bookdecade1910, booksubjecttheses, bookyear1912
