. Western electrician . at the right-hand roadway at each end- ofthe bridge and the signal at the center of the span are alsooperated by compressed air on a system devised by George , The center signal, Fig. 2, in general appearance issimilar to an ordinary railroad switch stand, with target andlantern, except in height, the top of the lantern being iSfeet above the roadway. It is placed on top of the extremeend of the center truss, its purpose being to convey signals tovessels, the red targei; by day and the red light by night sig-nifying that the bridge is down, and no target at day
. Western electrician . at the right-hand roadway at each end- ofthe bridge and the signal at the center of the span are alsooperated by compressed air on a system devised by George , The center signal, Fig. 2, in general appearance issimilar to an ordinary railroad switch stand, with target andlantern, except in height, the top of the lantern being iSfeet above the roadway. It is placed on top of the extremeend of the center truss, its purpose being to convey signals tovessels, the red targei; by day and the red light by night sig-nifying that the bridge is down, and no target at day and agreen light at night signaling Go ahead. Motion is givento thespindleby a diaphragm acted on by the compressed light iathe lantern is furnished by two 16 candle powerincandescent lamps. There are four lamps or two sets inthe lantern, on two distinct circuits, connected with a double-throw switch in tlie operators ;;e, so that if a filament mone of-the lamps is broken another can be instantly thrown. FIG. 2. ELECTRICALLY OPERATED ROLLING LIFT ERIDGmovement of the strut backward is to revolve the cam crank,which operates on a series of levers and shafts, withdrawingthe pin latches. At the same time a small wheel strikes thecam of the rack wheel, and the first of this latterwheel operating through the small wheel and the connectinglevers is to withdraw the latch from the tail girders. Thesetwo duties performed, the bridge is free to move, and thesucceeding motion of the operating strut begins to move thebridge. In closing, these movements are simply reversed,and the bridge is again locked. As previously stated, the lock at the center is only to pre-vent lateral movement. The arm to the center acts as acantilever; the tail girder, being the anchor, is held down byheavy anchor rods reaching to the bottom of the raising the bridge, the power from the operating strut iscarried from the center truss to the two outside trusses byheavy vertical b
Size: 1797px × 1390px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1880, bookidwesternelect, bookyear1887
