Patent GB-190105964-A (GB)
Title: Improvements in or relating to Electric Railway Signals.
Inventor: BOULT ALFRED JULIUS
Filed: 1901-03-21
Granted: 1901-07-27
Abstract: 5964. Boult, A. J., [Price, J. D., and Council, W. H.]. March 21. Signalling a n d communicating b e - tween trains; signals on engines &c. ; contacts, electric.-The rails 25, 29 of the track are divided into insulated block sections 2, 3, 4, &c., by insulations 27, 28, 31, 32 and comparatively short interposed rails 26,30. When a section, say 4, is clear, the electromagnet 41 connected to the rails 25, 29 at the rear end of the section is energized by a battery (corresponding to the battery 33 of the section 3) at the advance end of the section, and holds the switches 44, 45 of the track installation 5<1> in the position shown. In this position, the switch 45 closes the circuit from the battery 34 of the installation 5<1> through the contacts 37, 36, conductor 49, rail 30. conductor 40, switch 44, and electromagnet 35 of the installation 5, conductor 39 to the rail 29 of the section 3, and conductor 48 back to the battery, while the switch 44 closes the corresponding circuit between the installation 5<1> and the next installation in advance. The electromagnet 35 of the installation 5 is thus energized, and holds the circuitreversing armature 36 in the position shown, the positive pole of the local battery 34 being connected through the contacts 37, 36 and conductor 49, to the rail 30, while the negative pole is connected through the contacts 38, 47 and conductor 48 to the rail 29 of the section 2. The signal equipment on the engine cab &c. comprises a 'clear' signal 6 and a 'danger' signal 7, one or other of which is in the circuit of the battery 9 according to the position of the armature 10. This armature is operated by two permanent magnets 15, 16, and the solenoid coils 17, 18 connected by the conductors 19, 20, 21 to the locomotive wheels 22, 23, 24. Assuming, as before, that the section 4 is clear, when the engine comes into the position shown, the circuit 49, 48 of the battery 34 is completed from the rail 30, through the wheels 22, coils 18, 17, and wheels 23 to the rail 29, the armature 10 being thereby moved into or held in position to complete the circuit of the signal 6. The coils 17, 18 each have double reverse windings, which are both connected to the common conductor 20. When the wheels 23, 24 have moved into position to bridge the rails 29, 30, the current from the battery 34 passes in the reverse direction through the coils 17, 18, by the conductors 20, 21, but, as the current also passes through the reverse set of coils, the armature 10 is not moved. The conductor 21 thus serves as a safeguard in case of failure of the conductor 19. When the train enters the section 3, the battery 33 of that section is short-circuited, the electromagnet 41 of the installation 5 is deenergized, and the switches 44, 45 opened, thereby breaking the circuits of the electromagnets 35 of the installation 5 and of the next installation in the rear, with the result that the corresponding armatures 36 reverse the pole connections 37, 38 of the corresponding batteries 34 with their rails 29, 30. If, now, a second train enters the section 2, a reverse current passes through the coils 17, 18 and conductors 19, 20 on its engine &c. This current weakens the magnet 15, and strengthens the magnet 16, so that the armature 10 is moved over into position to complete the circuit of the 'danger' signal 7. At the entrance to the section 3 the action would be similar. When the first train leaves the section 3, the apparatus at the entrance to the section 2 is returned to the position for giving a 'clear' signal. Fig. 2 shows a modification of the signal apparatus on the engine. The electromagnet 55 in the closed circuit 59, aided by gravity, normally holds the armature 53 in position to complete the circuit of the danger' signal light 7. When the engine passes over an installation set for giving a ' line clear' signal, the normally open circuit 57, 56 is completed through the electromagnets and the track apparatus, the current so received weakening the magnet 55 and strengthening the magnet 54, so that the latter magnet raises the armature 53 into position to complete the circuit of the ' clear' signal 6. Fig. 3 shows another modification, in which the operating-magnets are permanent, and the solenoids 62, 63 have double reverse windings, as in the arrangement shown in Fig. 1. The normal current from the battery 61 through the coils holds the armature in the 'danger' position, whilst a line clear' current from the track apparatus passes through the reverse set of coils and reverses the armature.