. The Street railway journal . ion. The alternating current for the track circuits is supplied byspecial high-voltage alternating-current mains which run theentire length of the tunnel. These deliver current to the signalblocks at 500 volts potential, from which it is transformeddown at each block by a special double-secondary oil trans-former, one coil of which feeds the track circuit and the otherthe signal-lamp circuit. In this way the most economicalmethod of current supply is secured, while at the same timeabsolute independence of the various circuits is obtained bythe use of the transfor
. The Street railway journal . ion. The alternating current for the track circuits is supplied byspecial high-voltage alternating-current mains which run theentire length of the tunnel. These deliver current to the signalblocks at 500 volts potential, from which it is transformeddown at each block by a special double-secondary oil trans-former, one coil of which feeds the track circuit and the otherthe signal-lamp circuit. In this way the most economicalmethod of current supply is secured, while at the same timeabsolute independence of the various circuits is obtained bythe use of the transformers. The various magnet-control ap-paratus, which is used for operating the controlling air valvesfor the signal cylinders, receive current from a storage-batterymain which also runs the length of the subway. This mainis fed by several sets of 16-volt storage batteries in duplicate,which batteries are located at the various interlocking towersand are charged by motor generators. 652 STREET RAILWAY JOURNAL. [Vol. XXIV. No. WeRTED PLAN PLAN DETAILS OF THE NEW TYPE OF TRACK CIRCUIT RELAY USED. \\DESIGNED TO RESPOND TO ALTERNATING CURRENT ONLY THE SIGNAL MECHANISMlii the sketch at the right is shown in perspective the ar-rangement til* the apparatus installed at a hlock-signal sta-tion. As may be seen from the diagrammatic arrange-ment of this apparatus in the tunnel, it consists of, first, theblock signal and then a transformer, a case for the track-cir-cuit instruments and the automatic stop-valve box. The pur-pose of the transformer has already been referred to; it takescurrent from the 500-volt main through 3-amp. enclosed fusestu the primary coil; its secondary contains two coils, one ofwhich delivers current at 50 volts for use in the 4-cp incandes-cent lamps used in the signal, while the other coil delivers cur-rent at the lower voltage of 10 volts for use in the track cir-cuit. As may be noted, the leads to the track circuits passdown the instrument case and thence to
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectstreetr, bookyear1884
