. Operation of trains and station work and telegraphy . tching and delivering device. Theillustrations will serve to make this perfectly clear. As before mentioned, in taking out a staff the polarityof the operating current is reversed. This prevents asecond staff from being taken out of eithei* instrument, asfollows: The polarity of the current flowing through magnetK-360, Fig. 125, is never changed, the current for thesame being local. The polarity of the current flowingthrough K-88, Fig. 125, is changed each time its staff isput in or taken out of either instrument. This puts theinstruments
. Operation of trains and station work and telegraphy . tching and delivering device. Theillustrations will serve to make this perfectly clear. As before mentioned, in taking out a staff the polarityof the operating current is reversed. This prevents asecond staff from being taken out of eithei* instrument, asfollows: The polarity of the current flowing through magnetK-360, Fig. 125, is never changed, the current for thesame being local. The polarity of the current flowingthrough K-88, Fig. 125, is changed each time its staff isput in or taken out of either instrument. This puts theinstruments either in or out of synchrony. The magnet(Figure 125-K) is formed of two separate coils, oneenergized by the local and one by the line battery. Theconstruction of this magnet is such that when the cur-rents in both coils flow in the same direction, the lines offorce flow round the cores and connecting straps, thusforming no point of attraction for the armature. Whenthe current is reversed in one coil, the lines of force op- STATION AND TRAIN WORK 403. FIG. 124, ABSOLUTE STAFF INSTRUMENT. Front View of Instrument when a Staff is Released or about to beReplaced. 404 RULES FOR MOVEMENT OF TRAINS
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectrailroa, bookyear1919
