. Railway age . ddle of n track circuit section. The track circuit has urelay at each end. These are frequency relays, that Is to say. Fiy. ^—Signal Motor and Relays. relays which respond only to alternating currents of a given fre-quency. These control the signal circulls. At each end of the irarkcircuit there is also an inductame bond the iermlnals of whichare connected to the rails and the center of which Is connected toIhe center of the bond of the next tra:k circuit, thus forming ametallic connection around the Insulated rail joints for the returnpropulsion current. This center connection
. Railway age . ddle of n track circuit section. The track circuit has urelay at each end. These are frequency relays, that Is to say. Fiy. ^—Signal Motor and Relays. relays which respond only to alternating currents of a given fre-quency. These control the signal circulls. At each end of the irarkcircuit there is also an inductame bond the iermlnals of whichare connected to the rails and the center of which Is connected toIhe center of the bond of the next tra:k circuit, thus forming ametallic connection around the Insulated rail joints for the returnpropulsion current. This center connection may also be uee<l forcross bond taps. The inductance bonds were designed to carry the heavy cur-rent necessary with direct-current propulsion and also wereperfectly balanced lo offer Ihe least Impedance to anallernaiing propulsion current. In fact. If the external track re-turn Is perfectly balanced the only Impedance of the bonds maybe said to he ohmlc. The frequency relays are absolutely Immune. Fig. 3—Signal Cabin. Vernon, Conn. Januauy 17, 11)08. THE RAILROAD GAZETTE. 97 to a direct current or to alternating current of 25 cycles, havingbeen designed to operate at GO cycles. The unbalancing of the traclttherefore, even if sufficient to throw a heavy current through thetrequ(>ncy relays, would not result in a false clear signal indica-tion. This .system will, of course, be not in the least affected by;iny foreign trolley current. In connecting the inductance bondsto the rails is made of an old rail about 15 ft. long. To connectup an inductance bond to a track with broken or staggered joints,it is necessary either to cut one rail of the track so as to have the In Fig. 1 the 2,200-volt signal wire may be seen on the polewhich stands close to the signal. The 110-volt signal wires are onthe lower arm of the Western Union poles, situated at the extremeright of the photograph. The three-phase. 10,000-volt. 60-cycle, andthe three-phase, 11,000-volt, 25-cyel
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Keywords: ., bookcentury1800, bookdecade1870, bookidrailwayage44, bookyear1870
