Patent GB-190814784-A (GB)
Title: Improvements in Electrically Blocking a Single Line Railway.
Filed: 1908-07-11
Granted: 1909-08-11
Abstract: 14,784. Siemens Bros. & Co., [Siemens & Halske Akt.-Ges.]. July 11. Single-track systems; interlocking.-In a single track system, means are provided for cancelling a permissive signal at the receiving station as long as the starting-signal has not been pulled off, and for indicating at the first station while a train is on the line that the second station desires to send a train to the first as soon as the train from the first station has passed off the section. For these purposes five block elements are used at each station, four, I, II, III, IV, being of the type described in Specification No. 2923, A.D. 1872, while the fifth element S is of the type described in Specification No. 19,658, A.D. 1907, the elements I, III, S being normally free and elements II, IV blocked. The locking rods of elements I, II, III engage recesses in the tappet of the starting signal lever, and the locking rods of elements IV engage the tappet of the home signals, while an interlocking bar 35 is engaged by elements I, II, S. When station A desires to send a train, he signals by bell or otherwise to station B, on which B operates his element III to send a current from inductor J through line 1, contact 2, 3, locking magnet 4, line 5, contact 6, 7 to line 8 of station A, contact 10, 11, line 12, magnet 13, contact 15, the return being earthed. The element III thereby locks tte tappet 36 in station B, while the locking rod of element II in station A is released, and with it the tappet 36 so that the starting-lever may be pulled over. This permission may be cancelled, provided the lever has not been moved, by operating the element II and completing a circuit from inductor J at station A through line 1, contact 22, line 21, contact 20, line 18, contact 17, magnet 13, line 12, contact 10, and line 8 to station B, thence through the magnet 4 of element III, which is thereby unlocked, and the earth return. The apparatus is thus returned to normal. When, however, the starting lever is moved, a hump 45 on the tappet depresses the plunger S and breaks contact 22 in the cancelling circuit, and at the same time locking element S, and shifting the bar 35 to the right, the bottom of the locking rod moving down the incline of its notch. After the train has entered the section, the starting- lever is replaced, thereby remaking contact 30. The plunger rod I is then depressed, and this, by mechanical connexion, depresses plunger II. The first part of this movement completes a circuit from inductor J to lines 1, 34, magnet 33, line 32, contact 30, line 29, contact 28, line 18, contact 17, magnet 13, line 12, contact 27, magnet 46, line 47 to station B, magnet 48, contact 50 and earth return. The elements I, II are thus blocked and the element S is freed, while in station B the element IV is freed to allow of the pulling off of the home signal. In the second part of the above movement of the element I, its locking-rod returns the bar 35 to its normal position, the bar having been released by the freeing of the element S. If it is desired to send a train from station B immediately the first train arrives, permission is asked from station A, on which the element III of that station is depressed to free the element II at the station B, thus withdrawing the locking rod of this element from the tappet 35 and at the same time locking the element III and tappet 35 at station A, so that when the first train arrives at station B and the home signal there is replaced, the element III at that station and the element I at station A may be freed, by pressing the plunger of element IV at station B and completing a circuit from inductor J through line 1, contact 52, magnet 48, line 47 to station A, magnet 46, contact 25, and earth return through magnet 4. The starting-lever at station B may then be pulled over, or the permission obtained cancelled as before.