. Electric railway journal . of main-line track, and in-clude the elevated lines completed in 1901, the Washing-ton Street tunnel, the Forest Hills elevated extensionand the Cambridge subway. All train movements onthese lines have been controlled by block and interlock-ing signals from the beginning of service, and at present Jl Elevated H Washington St. H Tunnel J Atlantic ElevatedElectric Ity Journal Boston Elevated Signal Maintenance-Transit Lines -Diagram of Rapid about 250 signals are in use, all being of the UnionSwitch & Signal Companys manufacture and of theelectro-pneumat
. Electric railway journal . of main-line track, and in-clude the elevated lines completed in 1901, the Washing-ton Street tunnel, the Forest Hills elevated extensionand the Cambridge subway. All train movements onthese lines have been controlled by block and interlock-ing signals from the beginning of service, and at present Jl Elevated H Washington St. H Tunnel J Atlantic ElevatedElectric Ity Journal Boston Elevated Signal Maintenance-Transit Lines -Diagram of Rapid about 250 signals are in use, all being of the UnionSwitch & Signal Companys manufacture and of theelectro-pneumatic type. The signals in the Cambridgesubway are operated by alternating current, forty-fiveblocks being in service, while those in the WashingtonStreet tunnel and on the elevated lines are of the direct-current type. In the former case, the double-rail returnis used, and energy is supplied to the local transformersof the system from 550-volt mains, the feed to the trackcircuits being 10 volts maximum. The mains supplying. Boston Elevated Signal Maintenance—Signal Bridge, Cam-bridge Subway Line the direct-current signals are operated at 110 volts witha single rail return, the pressure drop across the trackrelays ranging from 15 volts to 20 volts. The Cam-bridge subway and the other rapid transit lines do notinterchange equipment, but all are operated under thedirection of a superintendent of rapid transit lines. ORGANIZATION OF SIGNAL MAINTENANCE WORK The maintenance of signals and interlocking and allnew construction in connection with either is handled bythe companys department of maintenance and way,headed by a chief engineer responsible to the chief ofmaintenance. Reporting to the former through thesuperintendent of rapid transit lines is a roadmaster ofrapid transit lines, and to the last-named official the headof the signal department reports, with the title of in-spector of signals. As shown in the accompanying dia-gram, the inspector of signals is assisted in executive
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Keywords: ., bookcentury1900, bookdecade1900, bookpublishernewyorkmcgrawhillp
