14,024. O'Donnell, J. P., and Glenn, S. L. June 10. Locking-devices. - Relates to means for controlling the switch-point lever e by a train approaching the switch points E wherein the lever is first locked owing to the presence of the train in the approach - section A, then freed for a short interval while the train is in the release-section B, nearing the signal governing the approach to the switch points, and finally locked until the train clears the section D, this section comprising the points. The electromagnetic lock f for the lever e is normally energized to free the lever by a circuit comprising a battery X and contacts g, b<1>, d<1>, the relative windings of the relays b, F being such that the armature h of the relay F is not normally raised. When the train enters the section A, the contact at g is broken and the lever e locked. On the train entering the section B, the relay b is cut out and the relay F sufficiently energized to close the contact h. The lever e is thus freed until the train enters the section D, whereupon the relay d is deenergized and the contact d<1> broken, so that the lever e remains locked until the train clears the section D. In the modification shown in Fig. 2, the relay F bridges the insulation l at the signal C so that the contact h is broken and the lever e locked as soon as the first pair of wheels passes the signal. An additional contact 16, controlled by the relay F, may be provided in connexion with a warning-instrument 17. The lock f may be arranged as a back-lock on the lever of the signal C so as to prevent the full return movement of the lever while the circuit of the lock f is broken, the point-lever e and signal-lever being fitted with the usual tappet interlocking-mechanism. To prevent the points E from being operated while a train on the release-section B is travelling at a speed such that it cannot be stopped inside the signal C, a retarding-device, shown in Fig. 3, may be fitted in the circuit of the lock f. The contact-maker 11 for the switch 12 is carried on a pivoted plate 1 a pin 7 on which engages a slot in an arm 8 linked to the lever G of the signal C. When the lever is put to safety, the plate is turned, against the action of a spring 9, to open the switch 12, and is held by the armature of a relay 14 engaging a notch 15 in the plate. If the lever G is then put in the danger position shown, the plate 1 is released on the train entering the section B, owing to de-energization of the relay 14, and returns to close the switch 12. The return movement of the plate is retarded by clock-work such as the wheels 4, 5 and fan &c. 6, driven from a pawl 13 pivoted on the plate. This retardation is such that a train moving above the predetermined speed enters the section D and breaks the contact d' before closure of the switch 12. An electro-magnet may be arranged in the circuit of the relays a, b so as to lift the pawl 13 out of gear when there is no train in the sections A or B.