File:Electric railway journal (1921) (14759312044).jpg

Identifier: electricrailway581921newy (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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of cases oftrouble has been made by keeping after the maintain-ors and sending out monthly comparative reports tothem. The telephone lines of the Illinois Traction Sys-tem have no protective apparatus or drainage coils,insulating transformers, etc., and interference is takencare of simply by transpositions. Ordinarily the linesare good and clear in spite of the fact that they arecarried on the same poles and only 30 ft. from the33,000-volt transmission line. The principal sourcesof trouble are from the trolley where a pull-off comesloose and throws up over the telephone line, and fromthe telephone line coming loose from an insulator andfalling down on the cross-arm. A graphic record is also kept of the number of casesof substation trouble, that is, instances involving a com-plete shutdown of the rotary converters. The record isdivided between those cases where the machine is outmore than an hour and where it is out less than an hour.A good many cases of potential trouble are caught by
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At Left. Combination Crossing-Bell Wigwag and Light Warning Installed at Forty Grade Crossings. the Thirty-five Light Indication Signals on I. T. S. At Right, Two of ing from high firing. Formerly, the inspector for thetraction company also gave each insulator a meggerhigh frequency and other tests, but since the resultsobtained have been so good and the manufacturer onhis own account puts insulators to such rigid inspection,all electrical tests except the flash-over have been dis-pensed with. No method of testing pin-type insulators while inservice has been found which is satisfactory on theIllinois Traction System. Formerly a test was madeby the use of a telephone receiver connected to twospikes, one driven into the pole high up and the otherdown low, in order to hear the static discharge whichwould result from a defective insulator. It was found,however, that some defective insulators were missedunder this test, and also that it was very difficult topick out the defective one, even

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