The Americana; a universal reference library, comprising the arts and sciences, literature, history, biography, geography, commerce, etc., of the world . T3 > = S ^ at c G hi rt 1, Sil 111 > 2 rt > C c3 ?5 XV:^ u > tj c n 0 = ji: »; u? .i:;::^ . - (fl «ffi p: t- Li C C I-. ^<i ^ di Cfl tfl STREET RAILWAY CONSTRUCTION Ojerhead Construction and TransmissionSystem.— In city work it is usual to suspendthe trolley wire directly above the centre ofthe tracks on a span or cross wire which is hungon poles erected at the edge of the double track roads centre poles have beener
The Americana; a universal reference library, comprising the arts and sciences, literature, history, biography, geography, commerce, etc., of the world . T3 > = S ^ at c G hi rt 1, Sil 111 > 2 rt > C c3 ?5 XV:^ u > tj c n 0 = ji: »; u? .i:;::^ . - (fl «ffi p: t- Li C C I-. ^<i ^ di Cfl tfl STREET RAILWAY CONSTRUCTION Ojerhead Construction and TransmissionSystem.— In city work it is usual to suspendthe trolley wire directly above the centre ofthe tracks on a span or cross wire which is hungon poles erected at the edge of the double track roads centre poles have beenerected between the tracks, and the trolley wiretarried on arms extending over the tracks; butthis practice is disappearing on account of the pressure of 500 to 600 volts, it is necessary tomaintain a high degree of insulation betweenthe current-carrying wire and the ground. Thetrolley wire is held up by a brass ear which isclamped or soldered on the wire. The ear issupported by an insulated hanger on the spanwire which in turn is fastened through one ormore insulators to the poles. In a well con-structed system there are three insulations be-. FlG. 5.— Typical double track trolley construction, section across Steel poles set in concrete; 2. Span wire; 3. Insulator; 4. Trolley hanger; 5. Trolley wire; 6. Track rails;7. Ties; 8. Feed wire insulators; 9. l*eed wires. obstruction in the street made by the centre tween the trolley wire and the pole. On small poles, and the danger of accidents to suburban single track roads the pole is«tten placed at the side of the track and the
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Keywords: ., bo, bookcentury1900, bookdecade1900, bookidamericanaunivers14newy
