Patent GB-360954-A (GB)
Title: Improvements in interlocking systems for railways
IPC: B61L21/06
Filed: 1930-08-11
Abstract: 360,954. Railway signals. GENERAL RAILWAY SIGNAL CO., Rochester, New York, U.S.A.-(Assignees of Lindner, J. C. ; 44, Gardiner Avenue, Rochester, New York, U.S.A.) Aug. 11, 1930, No. 24021. Convention date, Aug. 12, 1929. [Class 105.] In an electrical interlocking system of the dynamic indication type for operating railway points, a three-position relay is energized to close signal and other circuits when the points and point machine are locked in positions corresponding to the lever position and closes an indication circuit when de-energized; the common return wire for the point operating current also forms part of the indication relay control circuits. Means are provided to prevent false energization of the relay by any extraneous current; means are also provided to prevent false operation of the machine in case of a cross connection between operating wires. The operating circuits for the points pass through contacts operated by the points and the point machine, the contacts operated by the latter cutting off current at the end of the operation. In the arrangement shown in Fig. 1, a battery BT supplies energy to the points machine motor SM, over operating wires N, R and a common return C, through contacts 30 of a lever L ; the lever has an electric lock controlled by a track circuit on the points through an energy-saving catch-handle contact ; a track circuit indicator 44 is provided. The point motor is controlled directly by a polechanger PC, of which the contacts 5, 6 are normally operated by the point machine at the end of its movement, but are held during operation of the points, and also operated if it is required to reverse the points in mid-stroke, by series coils S<1>, S2 and shunt coils SH<1>, SH<2> energized from the lever through pole-changer coil contacts PCC; these contacts are operated by the throw-bar of the points, and assume intermediate positions whenever the point machine is unlocked. The point detector PD has three contacts 11, 12, 13 which open whenever the points are unlocked, and two special shunt contacts 14, 15 of which one is closed in each locked position of the points, while both are closed in any other position. The dynamic indication current passes through lever contacts 31 to energize one of two coils NI, RI of an indication current responsive device IR, which controls a dead-beat armature 33. A cross-protection relay CR is energized when current from the battery BT passes through coils 34, 35 in parallel, to open the power circuit at 37 and close the circuit of an indicator 42. The indication relay SS is an alternating current relay, having a local winding 38 and a line-phase winding 39 which is supplied by a transformer 20 over a line wire WP and the common return C. The operating circuits for relay SS include contacts 8, 10 operated by the point machine, detector contacts, armature 33 of the device IR, and lever contacts 32 ; the current in the coil 39 of the relay is reversed when the points are reversed, but is cut off unless all the apparatus has correctly operated; when the relay is de-energized, its contact assumes an intermediate position and operates an indicator 43. False energization during movement of the points is prevented by the detector shunt contacts 14, 15, which short circuit the wires WP, C, and is also prevented, in the case of a connection between the WP wires of two point circuits supplied from a common battery, by the impedance of the crossprotection relays CR, through both of which current from one circuit to the other must pass. Operation. In the position shown, with all apparatus normal, the line-phase winding of relay SS is energized from transformer 20 over detector contacts 12, 14, lever contacts 32, armature 33 of R, pole-changer coil contacts 8, and detector contacts 13. To move the points, the lever is moved to the left, opening the above circuit for SS and closing a circuit for the pole-changer coils S2, SH2 (to hold the pole-changer contacts) and the motor; this circuit passes from the battery BT through lever contacts 30 reversed, coil S<2>, polechanger contact 6, motor armature, pole-changer contact 5, motor field, coil 35 of relay CR, and contact 37, with pole-changer coil contact 7 and coil SH<2> in parallel with coil S<2> and the motor. As soon as the motor starts and unlocks the point machine, the pole-changer coil contacts are moved so that 8 opens and 9 closes, while 7 remains closed ; the circuit of SS is further broken at 8, but S2 and SH<2> remain energized, while SH<1> is connected to the normal operating wire at 9, so that if the lever is put back at any time during the operation S<2> and SH<2> will be de-energized by the opening of lever contact 30 reversed and SH<1> will be energized through lever contact 30 normal to move the pole-changer and reverse the motor. Continuing the operation, as soon as the points become unlocked, the detector contacts 11, 12, 13 open, isolating the transformer 20, and 15 closes to shunt the relay SS. On completion of the point movement, 11, 12, 13 close reverse contacts, and 14 opens; coil S<2> is short-circuited by contact 11. The point machine then completes its movement, closing pole-changer contact 10 and opening 7 to break the circuit of SH<2> and moving the polechanger contacts 5, 6 to their reversed position; the reverse operating circuit for the machine is thus broken and the normal operating circuit completed except for the lever contacts. The overrun of the motor then sends a return indication current through pole-changer contact 6 reversed, coil S<1>, wire N, lever contact 31 reversed, coil RI of the indication responsive device IR, both coils of relay CR, wire C, motor field and pole-changer contact 5 reversed. The armature of the device IR therefore moves over, and completes the reverse indication circuit for the relay SS from transformer 20 over detector contacts 13 reversed and 15, wire WP, contact 33 reversed of IR, lever contact 32 reversed, wire C, pole-changer coil contact 10, and detector contact 12 reveised. The detector shunt contacts 14, 15 are actuated by a cradle C, Fig. 3, pivoted on the end of a spring-pressed arm Y and having rollers which engage cam depressions in the detector operating bar D; the ordinary contacts 11, 12, 13 of the detector are carried on the same cradle, and all the moving contacts are arranged to have sliding engagement with the fixed contacts. The cradle C has a projection engaging with a groove in the lock plunger LP so that it is moved to its mid-position when the point machine is unlocked. The system may be applied to the operation of signals or other apparatus, and may be adapted for alternating current operation. Specification 169,795, [Class 105, Railway signals &c.], is referred to.