Patent GB-191102887-A (GB)
Title: Improvements in and relating to Electrical Systems and Apparatus for Railway Signalling.
IPC: B61L23/12
Filed: 1911-02-04
Granted: 1912-02-01
Abstract: 2887. O'Donnell, J. P., and British Pneumatic Railway Signal Co. Feb. 4. Electric operation and control.-Hand-levers with indication slots as described in Specification 183/00 are automatically moved through the last portion of the stroke by a solenoid deriving energy from the bus-bars through a circuit controlled by an indication relay and a contact on a lever moved by the hand-lever. The replacing solenoid for a points lever is controlled by an indication relay in a circuit including (1) the contacts of an indication selector which sets contacts according to the required direction to which the points are to be operated, (2) the contacts of detector magnets in circuit with contacts at the points to detect their full operation, (3) the contacts of a reversing-switch operated by the movements of the points locking-bolt at the ends of its stroke, the indication relay circuit being supplied with energy by the overrunning of the points motor after setting the points. The diagram shows the points lever 1 and the signal lever 62 together with the circuits required. The apparatus is shown in its normal position. To reverse the points, the lever 1 is pulled as far as is permitted by the roller in the slot 2. The contacts 8, 9, 10 are thereby closed. A circuit is made from positive bus-bar 23, through the magnet 22, indication selector magnet 14, contacts 8, reverse operating-wire 24, contacts 37 of the pole-changing switch, wire 70, motor armature 34, wire 71, contacts 38, field 72, and return lead 45<a> to the negative bus-bar 31. The magnet 36<a> is energized by a shunt circuit from the contacts 37 through the contact 42 of the pole - changer. The points are reversed and move the switches 28, 28<a> to the dotted position, thereby de-energizing the magnet 27, energizing the magnet 26, and closing the contact 26<a>. The last movement of the points locking - bar reverses the polechanger, closing the contacts 39, 40, 43, and the motor continues to run as a generator and supplies current from the armature 34, through contacts 40, field 72, lead 46, polarized relay 56, indicator bus-bar 19, and lead 76 to the indication relay 16<a>, the return being by way of the contacts 18, 17<a>, 26<a>, 9, normal operating-lead 25, contacts 39, and lead 71. The relay 16<a> closes the contacts 32 and completes a circuit from positive bus-bar 23 through lead 68, contacts 32, indication magnet 11, contacts 10, to the negative bus-bar. The magnet 11 lifts the rod 12 and completes the stroke of the lever 1 and breaks the last-described circuit at the contacts 10. The switchboard 49 carries the polarized relay 56, which controls a contact 57 in the main supply circuit to the bus-bars which is opened if the indication circuit receives a current by leakage in the wrong direction, thereby preventing operation of any points or signals. The circuit from the positive pole of the main supply 61 is through the galvanometer 51 and main switch 50, the coil 58 of which is controlled by the polarized relay contacts 57, to the positive bus-bar, and from the negative bus-bar direct to the negative of the supply through suitable resistances 60. A testing switch and lamp 51<a> are provided.