. The Street railway journal . tted lines compare the costs when a high-tensiontransmission line is required. The poles must then be con-siderably higher than when used for trolley purposes high-tension wires should be put out of reach of the trolley» pole. For this extra length of poles an increased cost of $3 perpole has been allowed. For the high-tension line forty polesper mile at a cost of $ in place are allowed. The result isshown in dotted curves B and D, Fig. 3. The cost of thirdrail, plus pole line, is at all points considerably lower than thecost of trolley line carrying
. The Street railway journal . tted lines compare the costs when a high-tensiontransmission line is required. The poles must then be con-siderably higher than when used for trolley purposes high-tension wires should be put out of reach of the trolley» pole. For this extra length of poles an increased cost of $3 perpole has been allowed. For the high-tension line forty polesper mile at a cost of $ in place are allowed. The result isshown in dotted curves B and D, Fig. 3. The cost of thirdrail, plus pole line, is at all points considerably lower than thecost of trolley line carrying high-tension wires. It so happens that a single No. 00 trolley wire and a yard soft carbon rail have almost exactly the same con-ductivity—133,000 circ. mil copper, making allowance forcables, bonds, etc. If the rail could be bought for $40per ton then the cost per mile of third rail would be$1,065. This includes an allowance for extra length of ties,cost of insulators, bonding, joint plates and provision for 200. FIG. IN COST BETWEEN TROLLEY AND THIRD RAIL ft. of cable at highway crossings. The 00 trolley would l>c$1,308, with copper at 14 cents and material on the same is not expected that the third rail will be installed in suchsmall sizes, but the comparison serves a useful purpose. The chief advantage of the third-rail system, however, is itslow maintenance cost. It is this feature which warrants itscontinued increased use, and no doubt will make it advisablefor many roads now using trolleys in high-speed service tochange to third rail. Assuming that a service, as shown in Run Sheet, Fig. 2,has been adopted, third rail and train control have been decidedupon, and the road is to be built in a manner successfully tocompete with the parallel steam line, while at the same timekeeping the investment as low as is consistent with per-manency, the details of construction are next to be cfmsidered. ♦^^^ The Consolidated Railway & Power Com
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectstreetr, bookyear1884
