File:The Street railway journal (1907) (14573374187).jpg

Identifier: streetrailwayjo301907newy (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

View Book Page: Book Viewer
About This Book: Catalog Entry
View All Images: All Images From Book
Click here to view book online to see this illustration in context in a browseable online version of this book.

Text Appearing Before Image:
l will be considerably extended, and the commercialand practical value of high potential transmission will bemuch increased. While both methods under consideration included high-tension transmission by alternating current, it was believedthat the combination method requiring transforming de-vices and continuous current motors was less well adapted circuits; the continuity of the overhead conductor is com-plete, and its position and height may vary within verticaland horizontal limits of 8 ft. and 4 ft., respectively, withoutlosing contact with the collecting shoes on the pantographframes. It is yet too early to furnish definite and positive compari-sons of cost of the two methods under consideration, butthe calculations and experience of the New Haven Rail-road Companys engineers indicate that the total cost of asingle-phase installation will be much less than that of thecontinuous current system, and that the higher electricalefficiency, lower fixed charges, maintenance and operating
Text Appearing After Image:
FIG. 1.—ONE OF THE INTERMEDIATE BRIDGES ON THE NEW HAVEN ROAD, SHOWING SEMAPHORE SIGNALS to the conditions than its simpler single-phase competitorfor many reasons. The electrical efficiency of the combina-tion system between power house bus-bars and engine shoesis 75 per cent only, as compared with 95 per cent for thesingle-phase system, the flexibility of the former is im-paired by the limited radius of the secondary low-tensiondistribution, requiring sub-stations at frequent intervals,and still further by the limitations imposed by the use of athird or conductor rail. The position and height of thisrail in its proper relation to the track rail must be rigidlymaintained, and the practical margin of permissible varia-tion is measured in fractions of an inch. Moreover, itscontinuity is broken at switches and crossings by frequenttransferrence of the conductor rail to the opposite side ofthe track or to an overhead position. In contrast, thesingle-phase system requires no sub-station

Note About Images