. The street railway review . ing and lighting. It will be perhaps that the Nantasket motor cars h«votwo trolley poles, as well a« contact shoes, and the .^hanging fromtrolley to third rail simply means the pulling down of the pole andthe closing of the third rail switch. THIRD KAII. AND REWKN flKllIT. Our thiid rail and return circuit experience will perhaps be ofvalue to both street railway and railroad managers, as we hav2undoubtedly made a wide departure from established have solved a number of interesting problems. Kirst Is the question of insulation. The third rail has
. The street railway review . ing and lighting. It will be perhaps that the Nantasket motor cars h«votwo trolley poles, as well a« contact shoes, and the .^hanging fromtrolley to third rail simply means the pulling down of the pole andthe closing of the third rail switch. THIRD KAII. AND REWKN flKllIT. Our thiid rail and return circuit experience will perhaps be ofvalue to both street railway and railroad managers, as we hav2undoubtedly made a wide departure from established have solved a number of interesting problems. Kirst Is the question of insulation. The third rail has a poten-tial of BOO volts above the ground and rests upon creosoted woodenblocks dowelled into the ties, its eaves being only 1% in. abovethe tie. Now it frequently happens that water accumulates 2 more in depth over the ties, and, if it were not for our cxperi-cnco to the contrary, we would naturally suppos-e that, under thesecircumstances, the line would be directly short clrcuiled beiwecu 748 (^t)i£d%\lvvai\%vlcw*. FIG. 5. the third and service rails through the water, the distance beingbut about 2 ft. each way. Nevertheless, we have been able *ooperate our road without the slightest difficulty when this hashappened, and nothing unusual has been noticed at the station,nor has the electrical output, as registered by the recording watt-meter been abnormal. At Berlin we have watched the ammeterclosely when we knew the tracks to be submerged in two places10 miles apart, during a heavy rain storm, and have found thatthe leakage was almost imperceptible when both cars on the linewere at rest and their air pumps out of circuit. At the same time,the wattmeter was standing still. Ot course, it a long length oftrack were submerged, the leakage might become serious, but wehave yet to learn how much is necessary to accomplish this result. We aim to so connect our third rail lines and the service railreturn as to have a practically complete metallic circuit ofextremely low resis
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Keywords: ., book, bookcentury1800, bookdecade1890, booksubjectstreetrailroads
