. The Street railway journal . of maintenance the bridges, track andother portions of a standard railroad. While the exacting con-ditions and heavy traffic of the present steam roads will re-quire for successful operation by electricity a carefully plannedand substantial construction, the lighter interurban roads mayfrequently be equipped with a less expensive system. Several classes of construction have been designed; of thesetlie least expensive type employing bracket arms will be de-scribed first. * Paper presented at a meeting of the American Institute of ElectricalEngineers, New York, Mar
. The Street railway journal . of maintenance the bridges, track andother portions of a standard railroad. While the exacting con-ditions and heavy traffic of the present steam roads will re-quire for successful operation by electricity a carefully plannedand substantial construction, the lighter interurban roads mayfrequently be equipped with a less expensive system. Several classes of construction have been designed; of thesetlie least expensive type employing bracket arms will be de-scribed first. * Paper presented at a meeting of the American Institute of ElectricalEngineers, New York, March 24, 1905. 6o8 STREET RAILWAY JOURNAL. [Vol. XXV. No. 13. BRACKET-ARM CONSTRUCTIONThis system consists of a single line of wooden poles spacedwell apart and fitted with bracket arms and steel catenary sus-pension cable for supporting the trolley wire. The bracket armis a T-iron supported by a tension rod at its outer endand fitted at the inner end with lugs which partly em-brace the pole and to which they are bolted with lag. tie-wires. The tension inthe messenger cable is ad-justed to give the propersag, and the trolley wireis pulled up tight enoughto take out all kinks andIjends. Both trolley andmessenger are then an-chored. The messen-ger is next clamped tothe insulators and thetrolley is permanentlysupported from themessenger by means ofhangers or clips whichare adjusted in lengthin such a manner as tohold the trolley hori-zontally. By this meansthe tension in the trol-ley is slightly relievedand allowance is made FIG. 1. screws. Fig. i indicates the construction. The in-inslator is of corrugated porcelain, cemented to amalleable-iron sleeve, which in turn is slipped over the bracketarm and held by clamps and set screws. The porcelain insu-lator has a groove at its center surrounded by a malleable-iron FIG. 6.—ANCHOR SCHEME collar similar to a pipe clamp. This collar has an eye on thelower side into which the hooks of a clamp which carries thesteel supporting cable or m
Size: 2247px × 1112px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1880, booksubjectstreetr, bookyear1884
