File:The Street railway journal (1906) (14761125605).jpg

Identifier: streetrailwayjo271906newy (find matches)
Title: The Street railway journal
Year: 1884 (1880s)
Authors:
Subjects: Street-railroads Electric railroads Transportation
Publisher: New York : McGraw Pub. Co.
Contributing Library: Smithsonian Libraries
Digitizing Sponsor: Smithsonian Libraries

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f the pole construction are 3^ins. X 3 ins. x 7-16 ins., while the offsets between 6 ft. and 10ft., the corner angles are ^^2 ins. x 3 ins. x J^ in. A drawingof the curve pole is shown in Fig. 11. The foregoing types of pole are each designed in the fourlengths. By reason of the uniform taper, an extra lengthdoes not result in an increase of the size of the corner angles,but only in the enlarged dimensions of the base. The moment of resistance at the base is thereby increased in proportion tothe height of the pole. Besides the standard poles above described, designed tomeet the ordmary conditions, an extra heavy pole was de-signed in three lengths. This type is called the strain pole,and is used for offsets up to 32^^ ft., for turning sharpcorners, or for anchoring the line at special points. Thesepoles are similar in design to the standard poles, but the taperis uniformly increased to ^2 in. to the foot, and all four sidestaper uniformly all the way to the top, which is 8j^ ins. x 12
Text Appearing After Image:
FIG. 13. -WOODEN-POLE CONSTRUCTION ON JAMAICA BAYTRESTLE ins. The base of the 41-ft. pole is about 5 ft. square, that ofthe 51-ft. pole being about 5 ft. 9^ ins. x 5 ft. 11 ^/^ ins. Thecorner angles of these strain poles are 4 ins. x 4 ins. x9-16 in. All the poles are designed to withstand the side strains on150-ft. spans due to the offsets above specified. For greateroffsets the length of span is shortened. At all sharp turns,three poles of the heavy-strain type are used, two to take thelongitudinal strains and guyed back to the base of the middlepole, which takes the side strains due to the offset. The three first-mentioned standard types of poles were de-signed to take the necessary side strains without guying. Thelongitudinal strains due to anchoring the lines are so great,however, that the strain poles used for anchorage are guyedfore and aft to the bases of the adjacent poles with 7-16-in.galvanized steel cable. On some sharp --urves the poles wereguyed laterally as an additionl

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