Patent GB-190301179-A (GB)
Title: Improvements in Operating and Controlling Railway Signals, Points and the like and Apparatus therefor.
Inventor: O'DONNELL JOHN PATRICK
Filed: 1903-01-16
Granted: 1904-01-14
Abstract: 1179. O'Donnell, J. P., and Irving, E. C. Jan. 16. Controlling and looking signals ; interlocking ; signalling between trains. - In a pneumatic system pf railway signalling and point. interlocking controlled by electric track relays, the presence of a train in a block section prevents the release by the forward cabin of the home signal in the rear cabin, the home signal being both positively and negatively locked by air power, and a special " King " lever being provided to effect a second interlocking of all point levers, and to permit of shunting when covered by the home signal. The apparatus used is of the type described in Specifications No. 183, A.D. 1900, and No. 5511, A.D. 1902. A complete block section is shown between home signals 2<a>, 2<b> at A and B, with insulated track sections 28, 31 at each home signal, and intermediate sections 29, 30. The interlocking slides 1, 2 operate the distant and home semaphores respectively, slide 3 releases the preceding slide 2, and may also operate a semaphore, while the " King " slide 4 further interlocks the point levers. On the arrival of a train at A with home signal at " danger," B is communicated with by telephone or otherwise and accepts by operating the slide 3, thereby closing a circuit from the positive line-wire 21, through contact 41<b>, the closed relay contact 48<b>, wire 68, relay contact 17, and the magnet of the electro-pneumatic valve 11 at A, to the negative line-wire 20. Air then flows from the supply pipe X' to force up the locking-piston 6 at A and, simultaneously, by means of the pneumatic cut-off valve 8, to stop the air supply to the cylinder M, so that the slide 2 may be operated and the home signal 2<a> set to "line-clear." The short-circuiting of the battery 29<a> produced by entry of the train into section 29 breaks the relay contact 77, and the consequent de-energization of magnets 16, 45<b> opens the contacts 17, 48<b> in the releasing-circuit for the slide 2. Simultaneous breaking of the contact 49<b> causes the electro-pneumatic valve 39 to admit air to the cylinder of the slide 3 at B, whereby the slide is half returned to the "block " position shown and the contact 41<b> broken, the mechanical interlocking being still maintained, and the half-return of the slide 2 at A being similarly effected so that the signal 2<a> moves to "danger" and the return indication current of air through the pipe n completes the return of its slide to the double-locked position, in which it must remain until the train reaches section 32 by virtue of the locking action of the de-energized valve 39 on the slide 3 at B. Entry upon section 30 breaks the contact 59<b>, and sets the signal 1<b> at B to danger by similar action to the above, and in section 31 the breaking of the relay contact 73<b> deenergizes the valve 47 and admits air to the cylinder 1<10> for the purpose of returning the slide 3 at B to the full block position, in which the point levers are unlocked, but the slide cannot be moved to release until the movement of the train into section 32 closes the relay contacts 62<b>, 48<b> and energizes the valve 39 so as to cut off air from the cylinder. While the train is in section 31, the distant signal 1<b> is also locked by the breaking of the contact 56<b>, and shunting can take place by pulling off the 11 King slide under full protection of the signals, the " King " slide maintaining the interlocking for this track section in the case of non- shunting trains. Means similar to the above may, if desired, be provided for unlocking the " King " slide while the train is in this section. Electric power may be substituted for pneumatic, and the positive and negative operation of the valves may be interchanged.