390 BELL SYSTEM TECHNICAL JOURNAL 



January 1940 issue of the Bell Telephone Quarterly. The ceremonies that 

 occurred at the time the line was opened for public service and the subse- 

 quent series of demonstrations of transcontinental service are also described 

 in that article. 



The new line had all of the latest improvements to provide regularity in 

 the loading. These ideas were also applied to the lines east of Denver, 

 making use of the new high-stability loading coils, and including respacing 

 of the loading points where desirable. Also, a great many changes in trans- 

 positions were necessary. In addition to the open-wire phantom group be- 

 tween New York and Chicago, there was one between Boston and Chicago 

 via Buffalo, and a New York-Bufifalo phantom group for use as part of an 

 alternate route to Chicago. Philadelphia, Baltimore, and Washington 

 were also connected to this network by additional phantom groups or by 

 non-phantomed pairs to Pittsburgh. 



As previously mentioned, the first coast-to-coast conversation occurred 

 on July 29, 1914 when President Vail spoke the first words to cross the con- 

 tinent. The engineering tests that preceded this ceremony had been made 

 on long isolated sections of the circuit. In the period that preceded the 

 opening of the New York-San Francisco circuits for public service on Janu- 

 ary' 25, 1915, a great deal of work was done to make the lines suitable for 

 commercial service and to train personnel in the operation and maintenance 

 of the lines, including the repeaters. In some sections, noise troubles^ 

 had to be cleared by special transpositions. Crosstalk conditions required 

 considerable attention. Some of the last minute improvements in the 

 repeaters and other apparatus were utilized. 



The New York-San Francisco circuits as first used commercially had some 

 temporary or experimental features, especially as regards the repeaters. 

 For several weeks, the transcontinental circuits used three intermediate 

 repeaters located at Brushton (Pittsburgh), Omaha, and Salt Lake City. 

 Then additional repeaters were used at Morrell Park (Chicago), Denver, 

 and Winnemucca. Later on, permanent repeaters were substituted for 

 the experimental repeaters. This change from three to six intermediate 

 repeaters was made primarily to obtain greater flexibility in operation and to 

 provide long-haul service, including leased telegraph service to some inter- 



^ This reference to noise reduction work on the transcontinental line makes it appro- 

 priate to mention at this point the very important fundamental investigation of inductive 

 interference between electric power and communication circuits which was made in the 

 period 1913-1917 by the "Joint Committee on Inductive Interference" appointed by the 

 Railroad Commission of the State of California in 1912. The field engineering staff which 

 planned and conducted the technical studies and prepared reports thereon included en- 

 gineers from the transmission division of the American Telephone and Telegraph Com- 

 pany Engineering Department. Mr. H. S. Warren made important contributions in the 

 planning and conduct of the investigation, and was elected to an honorary membership of 

 the committee. The conclusion and principal reports of the work have been published 

 and widely used (refer bibliography). 



