. The Street railway journal . e of trolley is on the San Francisco, Oakland & San JoseRailway, illustrated in the Street Railway Journal for , 1904. It is customary to install two pantagraph trolleys,each collecting its share of the current, and where necessary tocollect a larger amount, as might be the case in locomotivework, additional trolley contacts may be installed to any extentrequired. A pantagraph type of trolley, provided with a shoeinstead of a roller, is well adapted for use in connection withthird-rail operation, where it is desired to make overhead con-tact through special
. The Street railway journal . e of trolley is on the San Francisco, Oakland & San JoseRailway, illustrated in the Street Railway Journal for , 1904. It is customary to install two pantagraph trolleys,each collecting its share of the current, and where necessary tocollect a larger amount, as might be the case in locomotivework, additional trolley contacts may be installed to any extentrequired. A pantagraph type of trolley, provided with a shoeinstead of a roller, is well adapted for use in connection withthird-rail operation, where it is desired to make overhead con-tact through special track work or road crossings where thethird rail cannot be conveniently installed. On the New YorkCentral locomotive, this particular contact device is fitted withan air piston to provide a convenient means of depressing thecontact shoe. The ordinary methods of trolley wire suspension and insula-tion are not well adapted for high potential alternating trolleylines, and what is known as a catenary suspension of the trolley. FIG. 5.—PROPOSED FORM OF THIRD RAIL wire will probably be more generally used. In the catenarysuspension, the supporting cable or catenary is carried over thetop of high potential insulators at the point of support and thetrolley wire is attached by clips and hangers directly to thecatenary without intervening insulation. The catenary thusserves as a supplemental conductor to the trolley wire, and itmay be of either steel or copper. As the trolley wire is sup-ported at frequent intervals, the poles for the catenary can be spaced at longer distances than common with the ordinary typeof trolley construction. While especially advantageous for highpotential work, there is no reason why the catenary form ofsuspension should not be more generally employed for direct-current work, and it provides a means for supporting a largertrolley wire, if desired, than is now commonly used. Severaldetails of the catenary construction are shown in Fig. 4. The third rail, alth
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectstreetr, bookyear1884
