. Electric railway gazette . ame motor has tak-en a loaded car upa 12^ percent, gra-dient at a speed ofS miles per the exceptionof the Daft motor, Franklin, for ele-vated railway serv-ice, these are thelargest tractors everbuilt in the historyof electric propul-sion. The line at Pitts-burgh, though notin full operation,merits some speciald e s r i p t i o n, as itmakes use of under-ground and aerialconduction on thesame circuit. Theunderground con-tluctor occupies acontluit similar indesign,though muchsmaller, to those incable-traction, andthis difference insize, and in the ex-cavati
. Electric railway gazette . ame motor has tak-en a loaded car upa 12^ percent, gra-dient at a speed ofS miles per the exceptionof the Daft motor, Franklin, for ele-vated railway serv-ice, these are thelargest tractors everbuilt in the historyof electric propul-sion. The line at Pitts-burgh, though notin full operation,merits some speciald e s r i p t i o n, as itmakes use of under-ground and aerialconduction on thesame circuit. Theunderground con-tluctor occupies acontluit similar indesign,though muchsmaller, to those incable-traction, andthis difference insize, and in the ex-cavation which itentails, are fairlyproportional to thedifference in cost between them The price of 1that at Pittsburgh was $15,500 per mile. The,=disparity is further enhanced by substitution of;an imperishable copper conductor costing $1,200per mile for a cable whose lifetime is only eight-een months, and its price per mile ,|2,ooo. Put the most telling advantage claimed on theside of electricity lies in its superior ^-^:t«i;«,«^i» Ml anuary, lo THE STREET RAILWAY GAZETTE. 3f the total mechanical power involved in:able traction, the proportion applied to moving;he cable alone ranges from 84 to 65 per cent.—3r an average of, say, 75—leaving only 16 to 35:er cent, or an average of 25, available for pro-Dulsion. In brief, three quarters of the totaljffort of the prime mover is absorbed by prejudi-cial work and one quarter left for useful applica-;ion. With electricity, 70 per cent, of the totalenergy of the prime-mover is available for usefulA^ork on any circuit of the ordinary length of aitreet-railway, and only 30 per cent, consumed in:he conversion of mechanical work into current,md lice versa, and overcoming the resistances ofconduction. The effort of the prime-mover isdistributed in the ratio of seven-tenths to usefulvork and only three-tenths to prejudicial. Itshould be supererogatory to point out that thisiifference in efficiency at once prescribes the dif-
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Keywords: ., bookcentury1800, bookdecade1890, bookpublishernewyo, bookyear1895
