File:Electric railway journal (1917) (14781484293).jpg

Identifier: electricrailway501917newy (find matches)
Title: Electric railway journal
Year: 1908 (1900s)
Authors:
Subjects: Electric railroads
Publisher: (New York) McGraw Hill Pub. Co
Contributing Library: Smithsonian Libraries
Digitizing Sponsor: Smithsonian Libraries

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x to ten wiresare required between the switch point and the signal,the distance between these points usually being notmore than 200 ft. The long main-line track circuits utilize both railsand include impedance bonds. These track circuits areof three kinds—center fed, offset fed and end fed. With the center-fed type the track transformer is located atthe center of the block with a track relay at each end.With the offset type, the track transformer is locatedabout 1500 ft. from one end and up to about 1% milesfrom the other end, with a track relay at each end ofthe track circuit. This type of circuit is used to obtaina preliminary section without the expense of putting ina definite rail cut with insulating joints, impedancebonds and a track relay. This type of track circuit isused when the long end is not so long that it is im-possible satisfactorily to feed it. This length whichwill operate satisfactorily depends largely on ballastconditions. Roughly, the long end of offset-fed track
Text Appearing After Image:
T. H., I. & E. SIGNALS—INSULATED RAIL JOINTS, IMPEDANCEBONDS, AND CABLE POST WITH RELAY AND TRANSFORMERHOUSING AT END OF PRELIMINARY SECTION circuits may be 1% miles long. Above this length onecenter-fed track circuit and one end-fed track circuitare required to take the place of the one offset-fed trackcircuit. The end-fed double-rail type track circuits are usedwhen it is necessary to put in a definite cut for a pre-liminary track circuit. This type of circuit requiresthe installation of a 55-volt transformer at the end ofthe preliminary section. The 55-volt energy is run fromthe nearest signal location, which is generally not toexceed 2000 ft. away. Weber insulating rail joints were used in the presentsignal installation. The rail bonding comprises oneNo. 0000 conductor at every joint, electrically welded tothe head of the rail. Ballast conditions on the T. H., I.& E. are fair, and the ballast is, for the most part, keptclear of the rails. This ballast is mostly gravel, b

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