American telegraphy and encyclopedia of the telegraph; systems, apparatus, operation (1909)
Maver, William, jr. [from old catalog] · New York, Maver publishing company · leaf 613
HALL RAILWAY HLOCK SYSTEM—THEORY. ff the wires w,W become crossed, that will, by diverting current from km, place tnesignal at danger also. 502 AMERICAN TELEGRAPHY The relay r and the magnets are placed in any suitable place.One of the track instruments is shown in cross section in Fig. 377. In… … HALLS TRACK INSTRUMENT. tube. e,e are india-rubber * buffers above and below the lever, placed there toease the up and down motion due to the action of the wheels, and also to prevent any-thing short of a heavy weight from moving the lever. Normally, the end of the lever at the tube is down, owing…
Telegraph
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