US1527515A - Automatic train-control mechanism - Google Patents

Description

' J. L. HAYTER AUTOMATIC TRAIN CONTROL MECHANISM "Feb. 24. 1925.

Filed Aug. 4. 19 22 4 Sheets-Sheet 1 w mw auvemtoz 5 64 Feb. 24.-

J. L. HAYTER AUTOMATIC TRAIN CONTROL MECHANISM Filed Aug, 4, 1922 4 sheet -sheet 2 Feb. 24. 1925.

J. L. HAYTER AUTOMATIC TRAIN CONTROL uzcmmxsm Filed Aug. 4, 1922. 4 Sheets-Sheet 3 Feb. 24. 19.25. 1,527,515

J. L. HAYTER AUTOMATIC TRAIN CONTROL MECHANISM Filei Aug. 4, 19 2 I 4 Sheets-Sheet 4 Patented Feb. 24, 1925.

UNITED STATES PATENT OFFICE.

JOHN L. HAYTER, OF-NEW BRUNSWICK, NEW JERSEY, ASSIGNOR TO GEORGE E. MCCORMICK, OF NEW BRUNSWICK, NEW JERSEY.

AUTOMATIC TRAIN-CONTROL MECHANISM.

. Application filed August 4, 1922. Serial No. 579,591.

To all whom it may concern:

Be it known that I, JOHN L. Har'rnma citizen of the United States, residing in New Brunswick, in the county of Middle- The invention relates to an improvement in automatic train control mechanisms designed to reduce the speed of the train or to bring it to a full stop, according to road conditions as determined by the electric signal system with which the railway 1s equipped.

One object of the invention is to produce a train control mechanism which will control the operation of the brakes of the train according to the actual road condition, whether or not the signal indicates that condition. To this end an electro-magnet is provided, adapted for location in the'road bed of the railway and connected with the relay switches forming a part of the electric signal'system. By connecting the electro-magnet for actuating the brake operating device carried by the train with the re- 1ay switches of the signal system, the energization of the magnet is preferablycontrolled entirely by the road conditions ex-,

isting in the block withwhich the magnet is connected and is not dependent upon the operation of the signal which, as is wellknown, sometimes fails to operate and indicate the actual road condition.

A further object of the invention is to produce a train control mechanism which will operate, according to road conditions, to

reduce the speedof the train in one block, then if the road conditions, which call for the reduction of speed in the train still persist in the next succeeding block, to completely stop the train. If the road conditions in the next succeedingblock require caution in the block'which the train is entering (this situation being indicated .by the signal assuming a 45 position) the train control mechanism of the present invention operates to cause a service application of the brakes to thereby gradually reduce the speed of the trainas it proceeds through the block. There is a service application of the brakes under caution conditions at whatever speed the train enters the caution block,

' signal systems.

whether at high speed or Whether at a speed below that to which a service application of the brakes usually reduces the train. The object of this mode of operation is to insure such a reduction in the speed of the train that if the road conditions in the next block necessitate stopping the train by an e1nergency application of the brakes, the speed of the train will have been so far reduced that the emergency application of the brakes will cause a substantially instantaneous stoppin of the train.

Another and more general object of the invention is to simplify and improve upon the construction of automatic train control mechanisms in order to reduce the weight and cost of manufacture of such mechanisms and to'produceone which is adapted for application to existing equipments without material or expensive changes or alterations therein. These and other objects of the invention, which will appear as the description thereof proceeds, are accomplished ticularly pointed out in the appended claims.

The improved train control-mechanism is adapted for application to and use in conjunction with the more usual types of block Two-of these systems are in common and well-known use. In the first, the three position signal is controlled from a single relay box which contains all the contact points and switches for controlling the passage of the current from the battery to theisolenoids actuating the signal. This relay box is known technically as a three position relay. In addition to the various contact points, the relay contains a polarized magnet connected with the switches and energized by the battery of a pole changer-located in the next succeeding block. Thus the Lpolarity of the polarized magnet is change by the pole changer according to track conditions in the next succeedin block. The track conditions arcindicate by the signal connected with that block, and the signal ismechanically connected with the pole changer. In thesec- 0nd common type of block signal system, each block is provided with two separate relays corresponding .to the 90 or clear track position of the signal and to the 45 or caution position of the signal. The operatem which uses two separate relays for each block and the signal operating devices are controlled entirely by road conditions and not by' the signal of the next block, the train control mechanism operates to control the 4 Fig. 6 is an enlarged sectional detail throughapplication of the brakes entirely according to road conditions and irrespective of the positions of the signals. If the train con trol mechanism is applied to a signal system employing asingle three position relay in which the olarized magnet is connected with a pole cianger operated mechanically by a signal, then the train control mechanism operates partly in response to actual road conditions and partly in response to road conditions as indicated by the signal.

The preferred form of the invention is illustrated in the accompanying drawings in which Fig. 1 is a section through the valve for controlling the train .brake pipe and through the means for actuating the valve. The means for determining the operation of the valve is illustrated diagrammatically. Fig. 2 is a'longitudinal section showing the position of the parts' when the train brake pipe is connectedwith the emergency vent. Fig. 2 also shows the relation between the valve of the present invention and a standard engineers brake valve. Fig. 3 is a diagrammatic View showing'theposition of the armature and associated parts when an emergency condition exists in the track- Fig. i is a view similar to Fig. 2 showing. the position of the parts when the valve connects the train brake pipe with the service vent. Fig. '5 is a diagrammatic view similar to Fig. 3, showing the position of the armature and associated parts when a caution condition exists on the track.

one of the solenoid operated valves for admitting compressed air to one of the valve actuating pistons. Fig. 7 is a top plan of the engineers brake valve showing its relation to certain parts of the present mechanism. And Fig. 8 is a diagram of a block signal system employing a non-polarized circuit, and showing the connections between the system and the track magnet of the present train control mechanism.

The improved train control mechanism of the present invention, as illustrated in the drawings, comprises a track magnet located in the road bed of the railway. The track magnet may be placed at any preferred distance in advance of the block with which it is connected and whose track conditions are to control the oncoming train through the magnet. The track magnet is directly connected with the block signal system with which the railway is equipped. The block signal system is made use of to control the direction of current flow through the track magnet. 'If the current operating the switches in the relay box is shunted or short circuited from the relay, thereby indicating that a train is inthe block, a switch open, a

rail broken, or that some similar condition prevails, the current from the relay battery will flow through the track magnet in one direction to bring about an emergency application of the brakes on the oncoming train. If the preceding train has just left the block, so that the relay is "again placed in circuit, this situation being known as a caution condition of the block, the current flows through the track magnet in the opposite direction, thereby eifecting a service application of the brakes on the oncoming train. If the track conditions prevailing in the block require an emergency application of the brakes. this will be automatically effected under all conditions by the train 'track conditions or will be controlled by the track conditions as indicated by the position of the signal will depend upon the type of block signal system with which the railway is equipped. When a signal system having a three position relay is used and the system includes a pole changer for changing the polarity of the contact points in the relay box, the usual construction is to have the opera tion of the caution signal of the first block (under consideration) depend upon the mechanical operation of the next succeeding signal. Under these conditions the automatic service application of the brakes will depend upon the operation of the next succeeding signal. But'where a signal system is used which is not provided with either polarized contact points or a pole changer, then the serviceapplication of the brakes will be controlled directly by track conditions. The automatic train control mechanism of the present invention will be described in connection with these two standard types of block signal systems.

The polarized track magnet is adapted to actuate a constant pole armature carried by the train. The armature controls theoperation of a three position valve which is connected with the train brake pipe. If the armature is moved in one direction by the track magnet, the valve is moved to connect the brake pipe with a service vent and so bring about a service application of the brakes. If the armature is moved in the opposite direction by reason of the track magnet having an opposite polarity, thevalve is .moved to connect the brake pipe with an .at 10. The valve comprises "a cylindrical casing 11 which houses the valve proper 12 more fully hereinafter. the eng neers valve is shown in Fig. 7 In formed as adouble ended piston and having a recessed middle portion 13. The valve casing .11 is provided with a central opening adapted to be connected with the train brake pipe 14. The three position valve is operated independently of the engineers valve indicated at 15; and the engineers valve in turn may be operated independently of the three position valve, as indicated in the drawings. However, if the track con- ,ditions automatically effect an operation of the three position valve either to cause a service or an emergency application of the brakes and the engineer turns the handle 16 of his valve to either service or emergency position, then the three position valve will be restored to normal position, as shown in Fig. 1. This mode of operation will appear The handle 16 of the osition it occupies when the train is running.

The valve casing 11 is also provided with a service vent 17 and an emergency vent 1.8. When the track conditions require a service application of the brakes, the valve 12' will be moved to the right, as shown in Fig. 4, thereby connecting the brake pipe with the service vent and so bring about a service application of the brakes. If, however, the track conditions require an emergency application of the brakes, the valve 12 will be moved 'to the left, as shown in Fig. 2, and thereby bring about an emergency application of the brakes.

The illustrated means for actuating the three position valve 12 comprises two pistons 2i) and 21 located respectively in the. cylinders 22 and 23 which are secured at their inner ends 24 to the flangedv outer ends 25 of the valve. casing 11.. .The pistons 20 and 21 are mounted on the outer ends of the piston rods 26 screwed into the ends of the valve 12. Two compression springs 27 and 28 interposed between the ends of the valve and diaphragnis 29 serve to hold the valve in normal position, as indicated in Fig. l.

The pistons 20 and 21 which actuate the valve 12 are moved by means of compressed air. The compressed air is admitted to the piston 20 through a solenoid controlled valve 30 connected at its lower end3l with a source. of compressed air, preferably the. main reservoir on the engine. The solenoid 32 is wound in the usual manner and is adapted to actuate, when energized, an armature 33. Thearmature 33 is provided with a downwardly extending rod 34, the lower end of'which carries the stem 35 of a valve 36 normally pressed upwardly against its seat by a spring 37. When the track conditions require a service application of the brakes, the solenoid 32 is energized to draw the armature 33 downwardly and thereby unseat the valve 36. The com: pressed air then passes through the spider 38, up through the valve opening and into the cylinder 22. pushing the piston 20 and the valve 12 to the right to connect the brake pipe with the service vent. The downward movement of the armature rod causes the valve 40 formed on the lower end of the rod to close the rent 41. 12 remains in its moved position (as will hereinafter appear) until the engineer breaks the circuit connected with the sole noid 32 by shifting the handle 16 of the engineers brake valve 15 to service position indicated by the dot and dash line 42 in Fig. 7, or (if the service application of the brakes should stop the train) until the engineer turns the handle 16 to release position indi cated by the dot and dash line 39. An automatic emergency application of the brakes also breaks the circuit of the solenoid 32, as will presently appear. \Vhen the solenoid 32 is deenergized, the sprin 37 lifts the armature-rod 34, closing the valve 30 and opening the relief valve 40, t-herebypermitting the air to escape out through the vent 41. The spring'2S then restores the valve 12 to. itsnormal position.

When the track conditions require an emergency application ot the brakes, cont pressed air is admitted to the piston 21 through a solenoid controlled valve 43 to move .the valve 12 to the left and thereby connect the brake pipe with the emergency vent 18. The valve 43and its solenoid l4 are constructed and-operate exactly like the valve 30 and its solenoid 32, and therefore do not require a detailed description. The corresponding parts of both valves are indicated by the same reference numerals in the enlarged detail in Fig. 6.

The solenoids 32 and 44 are located in normally open circuits. hen these circuits are closed the solenoids derive their energy from the battery 45. The solenoid circuits are adapted to be closed when the permanent The valve magnet 47, which serves as an armature, is actuated by the track magnet 48. The armature 47 and its connected mechanism are enclosed in a housing, which for clearness of illustration is not shown. This housing is so located on the engine that the lateral extensions 49 and 50 of the lower end of the armature pass in close proximity to the upper ends of the poles 51 and 52 of the track magnet 48. The armature is pivotally mounted at 54, so that its upper end 56,

which serves as a circuit closer, may swinginto contact with either the contact points 57 or the contact points 58. The lower end of the armature having a permanent polarity and the polarity of the poles 51 and 52 of the track magnet 48 changing according to track conditions, itwill be seen that the armature will be swung in different directions according to the polarity of the track magnet.

It is assumed that the lower end of the armature 47 is a constant north pole, and that when emergency conditions obtain in the block the current directed'through the track magnet will cause the pole 51 to be north and the pole 52 to be south. The armature will then swing in a clockwise di-. rection (as shown in Fig. 3), thereby bringing the contact head 56 across the contact springs 58 and closing the circuit in which the solenoid 44 is located. The circuit may be traced as follows: Starting from the point 61 at the solenoid 44, the current passes through the wire 62 into the contact are 63 and thence throughthe handle 16 of the engineers valve 15 into the negative side of the battery 45. From the positive side of the battery the current passes through the wires 65, 66, 67 and 68 to the stick magnet 69. From the stick magnet 69 the current passes through the wire 71, through the contact points 58 and through the wires 72 and 73 to the solenoid 44. Then the engineer has turned the handle of the brake valve 15 to emergency position as shown by the dot and dash line 64 in Fig.

7, the contact point 74 (Figs. 2 and 7) passes beyond the end of the contact are 63, there by breaking the circuit in which the solenoid 44 is located and permitting the three position valve 12 to return to normal position. The turning of handle 16 of the engineers valve to release position when the train has been stopped by an automatic emergency application of the brakes also .restores the valve parts to normal position by breaking the circuit of solenoid 44.

When service conditions obtain in the block and the current is directed through the track magnet in the opposite direction so as to reverse the polarity of the poles 51 and 52, making the pole 52 north and the pole 51 south, the armature 47 is actuated to swing in a counter-clockwise direction, (as shown in Fi 5) thereby bridging the contact springs 57 through the contact head 56. The bridging of the contact springs 57 places the solenoid 32 in circuit with the battery 45. This circuit is traced as follows :Starting at the solenoid 32 the current passes through the wire 76 to the contact are 77, and thence through the handle of the engineers valve to the negative side of the battery. From the positive side of the battery the current passes the wires 65, 66, 67 and 78 to the stick magnet 79. From the magnet 79, the current passes through the wire 80 to the bridged contact points 57 and thence through the wires 82 and 83 to the solenoid 32. When the engineer turns the handle of the brake valve to service position in response to caution conditions on the track, the contact point 85 passes beyond the end of the contact are 77, thereby breaking the circuit in which the solenoid 32 is located, and permitting the valve 12 to return to normal position. Also when the engineer-turns the handle of his brake valve to release position the circuit through the solenoid 32 will be'broke n, and the valve 12 will be'turned to normal position.

The means for holding the armature in its moved position to keep the circuits of the of magnets 69 and 79 which are known in the art as stick magnets. When the armature 47 has been swung in a clockwise direction, closing the circuit through the solenoid 44 and incidentally energizing the magnet 69, an armature'piece 87 carried by an insulating block 88 mounted on the armature 47 is attracted to and held by the magnet 69, thereby keeping the contact springs 58 bridged until the engineer breaks the circuit by movinig the handle of his brake valve to emergency position or to release position. In like manner, when the armature 47 has been swung in counter-clockwise direction. thereby bridging the contact springs 57 and closing the circuit through the battery 45 and the solenoid 32, the magnet 79 is incidentally energized, and the armature piece 89 carried on the other end of the block 88 is attracted to and held fast by the magnet 79. Thus the contact springs 57 are kept bridged and the solenoid 32 energized until the circuit is broken by the engineer. If there has been an automatic serviceapplication of the brakes and the engineer does not turn his valvehandle to service or release position, and the train approaches the emergency block, the track magnet 48 being stronger than the stick magnet 79, the attraction between magnet 79 and armature 89 will be overcome when the track magnet actuates the armature 47 to expect an emergency application of the brakes. The breakmg of either circuit permits the balance solenoids 32 and 44-clo'sed comprises a pair springs 90 and 91, connected with the upper end of the armature 47, to return and hold it in normal position. To increase the magnetic flux through the pole pieces 49 and 50 carried'by the lower end of the armature 47 anelectro-magnet 93 in constant circuit with the battery 45 is provided. This circuit is side of the battery 103 through theswitch traced/from the positive side of the battery throdghthewires 65, 66,67, 78 and 94 to the magnet 93. From the magnet the current passes through the wires 95, 90, 97 and 98 to the negative side of the battery.

The connections between the track mag- -net 48 and a block signal system having 104 and wire 105 to track 101, and from there through the wire 106 to the relay box 107, and from the relay box through wire 108, the track 100 and switch 109 to the negative side of the battery 103. Vhen the relay 107 is receiving current from battery 103, while the contact switches 104 and 109 arein the positions indicated in full lines in Fig. 1, (this being their normal position, with the track in. block Y clear), the switches 110 and 111 are picked up against the con- I tact points 112 and 113, and the switches 120 and 121 are in engagementwith the contact points 122 and 123. The switches 104 and 109 of pole changer 102 are mechanically connected witif the signal 99 of block Y. When signal 99 is in clear or caution position (the track of block Y being clear) the switches 104 and 109 are held innormal position by the signal.

The points 112 and 113 are in circuit with the solenoid which controls the caution position of the signal 128, and the points 122 and123 are in circuit with the solenoid which controls the clear position of said signal. The caution position solenoid circuit is made from the battery 114 through the switch 110 and the point 112 to the solenoid. From the solenoid the current returns through the point 113, the switch 111 and the wire 115 to the battery 114. The clear position solenoid circuit is made from the positive side of the battery through the switches 110 and 121 to the contact point 122 and thence to the solenoid. From the solenoid the current returns through the point 123, the switches 120 and 111, and the wire 115 to the battery. Thus when the pole changer is in normal position, the signal 128 is held in its 90 or clear position. When, however, the switches 104 and 109 have been swung into contact with the points 117 and 118, owing to the fact that a train has passed into block Y and .the signal 99 has dropped to "zero or stop position, the polarity of thecontact points in the relay box 107 is changed, as will be seen by tracin the circuit from the positive side of the battery 103.

Before the train entered block Y it'pass ed through block X, and that caused relay 107 to be shuntedv from battery 103. Thereupon the switches 110 and 111 broke contact with the points 112 and 113 and signal 128 .fell to zero or stop position, as shown.

\Vhen the train passed out of block X and into block Y thereby putting relay 107 into circuit with the pole changer 102 again, the switches 110 and 111 were brought into contact with the points 112 and 113 and the signal 128 was raised to 45 or caution position. When the polarity of the relay 107 was thus changed the switches 120 and 121 broke contact with the points 122 and 123. When the train leaves block Y, switches 104 and 109 return to normal position (with the return of signal 99 to its 90 or clear. position) and the polarity of relay 107is restored to normal with the result that switches'120 and 121 again contact with points 122 and 123 and the signal 128 is raised to its 90 or clear position.

Assuming now that a train, indicated by the truck 125, has entered block X, the current from battery 103 is shunted by the truck and the relay 107 cut oil. The

switches 110 and 111 drop out of connection '3 -with the points 112 and 113 and into con tact with the points 126 and 127. lVhen this occurs the current ceases to flow through the switches 120 and 121, although they still remain in contact with the points 122 and 123, and the signal 128 drops to its zero or stop position. This situation requires an emergency application of the brakes. Accordingly, current is caused to flow from the battery 114 through. the track magnet 48 in a direction to bring about a connection between the train brake pipe and the emergency vent in the manner described above. This current passes from the battery 114'through the switch 110, the point 126 and the wire129 to the pole 51 making it a north pole; and from the latter through the connecting wire 130 to the pole 52, making it a south pole. From the pole .52 the current returns through the wire 131 to the point 127, the switch 111 and the wire 115 to the negative side of the battery.

When the train has left block X, thereby placing. the relay 107 in ,circuit again with battery 103, the switches 110 and 111 are 1 or caution position. This condition in the relay box 107 causes the switches 120 and 121 to be disconnected from the points 122 52, and through the wire 130 to the pole 51. From the pole 51 the current returns through the wire 129, the point 134, the

switches 120 and 111 and the wire 115, to the negative side of the battery.

The use of the track magnet of the automatic train control mechanism of the present invention in connection with 'a block signal system of the non-polarized circuit type is illustrated diagrammatically in Fig. 8. The drawing is a conventional representation of a standard form of signal mechanism. The track magnet 48 is shown connected with the signal circuit in such manner that the pole 51 will be north during an emergency condition in theblock with which the magnet is connected, and the pole 52 will be north during a caution condition in the block. When the track is clear, the track magnet will be cut off from the signal battery. It is assumed thata train, represented by--the truck 140, has

5 passed through blocks Av and B and has entered block G. This causes the current from the battery 141 tobe short circuit from the relay box 1421 Thereupon the switches or stop position.

144 fall upon the dead contactpoints 159 and 160, and the switches 151 and 152 fall upon the contact points 162 and 163, which are" connected respectively with the vires 164 and 165, thereby establishing a circuit from the battery 166 to the track magnet 48. The circuit is traced from the positive side of the battery through the wire 168,

the switch 152, contact point 163 and the Wire 165 to the pole 51, making the latter north. From the pole 51 a current passes through the wire 169 into the pole 52 making the latter south, and from the pole 52 the current returns through the wire 164, the contact point 162, switch 151 and the wire 17 0 to the negative side of the battery. Thus the track magnet 48 is energized to bring about an emergency application of the brakes in case the next train should attempt to enter block 0.

\Vhen the train left block B and entered block C, the battery 172 became connected again with the relay box 173. Inasmuch as the contacts and wires in relay box 173 are the exact duplicate of those in relay box 142, the same reference numerals will be used to indicate them. When the current from battery 172 again passes through relay box 173, the switches 143 and 144 are picked up against the points 145 and 146, the switches 147 and 148 are'picked up against the points 149 and 150 and the switches 151, 152 and 153 are picked up against the points 154,

155 and 156, with the result that the signal 175 is raised from stop position to caution position as indicated. Under these conditions, the current from battery 176 flows through the track magnet 48 in the reverse direction, making the pole 52 north and the pole 51 south, to bring about a service application of the brakes in case a train should enter block B. The circuit is traced from the positive side of the battery through the Wire 177, the switch 147 and contact 149 to the switch 178. From switch 178 the current passes through the wire 179 to the pole 52 and from pole 52 to the pole 51. From the pole 51 the current returns through the wire 180'to the switch 181, and from the switch 181 through'the wire 182 to the contact point 150 and switch 148 tothe negative side of the batteryp Whilethe signal 175 of block 15 is in caution position, signal 184 of block A will be in its 90 or clear track position. The clear track position of the signals is controlled by the caution position of the next succeeding signal, and the signal is lifted into clear position by the battery of the next suc ceeding relay box. Thus when the signal 175 of block B is in caution position, the circuit from battery 176 to the solenoid 185, which controls the position of signal 184, is traced through wire 168, switch 152 contact point 155 and wire 186 to contact 156 and switch 153 (of block A) and through wire 188 to the solenoid 185. From the solenoid the current returns through wire 189 to contact 154 and switch 151 (of block B) and through wire 170 to the negative side of the battery. It will have been observed that the lifting of switches 151 and 152 (of block 13) against contact points 154 and 155 broke the emergency connection between battery 176 and the track magnet. In like manner, it will beobserved that the energization of the solenoid 185 lifts the switches 17 8 and 181 and thereby severs the track magnet from battery 190.

Briefly, the operation of the improved automatic train control mechanism is as follows :-When the track conditions in a block require an emergency application of the brakes, current from the battery of the block signal system passes through the track magnet 48 in a direction to make the pole 51 north and the pole 52 south. This causes the pole 51 to repel the arm 49 of the arma ture 47, and the pole 52 to attract the arm 50, thereby swinging the arm 47 in a clockwise direction and closing the circuit through the solenoid 44 by bridging the contact springs 58 by means of the contact head 56. At the same time the magnet 69 is energized to attract the armature piece 87 and hold the contact head 56 in engagement With the contact springs 58. The en ergization of the solenoid -14 opens the valve 43 in the manner described and permits air under compression to enter the ,cylinder 28 and force the piston 21 and valve 12 to the left, as shown in Fig. 2. Thus the train brake pipe 14 is connected with the emergency vent 1S, and the result is an emergency application cf the brakes. This position of the parts of the train control mechanism continues until'the engineer turns the handle of the brake, valve 15 to emergency position or to release position, thereby disengaging the contact 74 from the contact are 63 and breaking the circuit through solenoid 4st, which permits the parts to return to normal position. i When the track conditions of. the block require a service application of the brakes on the oncoming train, current from the block signal system flows through the track magnet in the opposite direction n'iaking the pole 52 north and the pole 51 south. The arm 50 is now repelled by the pole'52, and the arm 19 is attracted by the pole 51. This action swings the armature 47 in acounter-clockwise direction, so that the contact head 56 bridges the contact springs 57 and energizes solenoid 32. At the same time,

the stick magnet 79 is energized ;to attract 32 and permitting the parts to return to normal position. If the train is proceeding at such rate of speed that the automatic service application of the brakes completely stops the train, the turning of the handle of the engineers valve to release position breaks the circuit through solenoid 32 and the parts of the train control mechanism are restored to normal position.

In the foregoing description of the mode VVhen a train isin a block, that constitutes a danger condition in that block. When the train leaves that block and enters'the next smceeding block, the latterbecomes the dan-. ger block and the former becomes the caution block. Under these circumstances, there would, of course, be first a service application of the brakes it an oncoming train attempted to enter the caution block and then an emergency application of the brakes it the train attempted to enter the danger block.

Having thus described the invention what I claim as new is 1. An automatic train control i'i'iechanism having, in combination, a magnet located in the road'bed of the railway and connected With the block signal system, the connections between the magnet; and the signal system being such that an emergency condition of the track causes current to flow through the magnet in one direction and a caution condition of the track causes the current to flow through the magnet in the op posite direction, a permanent pole armature carried by the train to pass in close proximity to the magnet, a valve connected with the train brake pipe and having a service vent and an emergency vent, and means for actuating the valve, said means being'controlled by the armature to connect the brake pipe with either the service vent or the emergency vent according to the polarity of the track magnet.

2. An automatic train control mechanism having, in combination, a track magnet connected with the block signal system, an emergency condition of the track causing the current to flow in one direction through the magnet and a caution condition of the track causing the current to flow through the magnet in the opposite direction, a permanent pole armature carried by the train to pass in close proximity to the track magnet, a valve adapted to.be actuated to connect the train brake pipe with a service vent and with an emergency vent, means for actuating the valve, and means connected with the armature for controlling the valve actuating means according to the polarity of the track magnet.

An automatic train control mechanism having, in combination, a track magnet the direction of current flow through which is controlled by a block signal system aecord- .n'eeted with the block signal system, an

emergency condition of the track causing the current to flow through the magnet in one direction and a caution condition of the track causing the current to flow in the op po'site direction, an armature carried by the train to pass in close proximity to the track magnet to be moved thereby in one of two directions according to the polarity of the magnet, a valve adapted to connect the train brake pipe with an emergency vent or with a service vent according to the direction in {which the armature is moved, compressed 'air operated means for actuating the valve,

and means connected with the armature for controlling the passage of compressed air to the valve actuating means.

5;"An automatic train control mechanism having, in combination, a track magnet connected with the block signal system, the curent' directions according as, emergency or rent flowing through the magnet in differcaution con'ditions prevail in the block, a

, valve adapted to be actuated to connect the train brake pipe with a service vent or with an emergency vent according to the polarity of the track magnet, and means carried by the train and adapted to be actuated by the track magnet for controlling the actuation of the valve.

1 6. An automatlc tram control mechanism having, 1n combination, a valve adapted to be actuated to'connect the trainbrake pipe with an emergency vent and with a service vent, means for actuating the valve, an ar- ,mature carried by the train for controlling the valve actuating means, a magnet located in the road bed of the railway adapted to rctuate the armature, and connections between the magnet and the block signal system to cause current to flow through the magnet in one direction for an emergency condition of the track and to cause'the cur rent to flow through the magnet in the opposite direction for a caution condition of the track.

7. An automatic train control mechanism having, in combination, a magnet located in the road bed of the railway, connections between the magnet and the block signal system whereby the current flows thro gh the magnet in different directions accor ing as an emergency or a caution condition prevails in the block, an armature carried by the train to pass in close proximity to the track magnet and adapted to be moved thereby in one of two directions according to the polarity of the magnet, a valve connected with the train brake pipe and having a service vent and an emergency vent, and means controlled by the armature for operating the valve to connect the brake pipe with either vent.

8. An automatic train control mechanism having, in combination, a two pole track magnet connected with the block signal system, an emergency condition in the block causing the current to flow through the magnet in one direction and a caution condition in the block causing the current to flow through the magnet in the opposite direction, an armature carried by the train to pass in close proximity to the track magnet, said'armature having lateral arms of fixed polarity so that the armature is moved in different directions according to the polarity of the track magnet, two solenoids in normally open circuits adapted to be closed by the armature, a valve adapted to be actuated to connect the train brake pipe with an emergency vent or with a service vent according to the polarity of the track magnet, compressed air-operated means for actuating the valve, and means controlled by the solenoids for regulating the passage of air to the valve actuating means.

9. An automatic train control mechanism having, in combination, a track magnet connection with a block signal system whereby an emergency condition of the block causes current to flow through the magnet in one direction and a caution condition of the block causes current to flow through the magnet in the opposite direction, a valve adapted to be actuated to connect the train brake pipe with a service vent or with an emergency vent according to the polarity of the track magnet, compressed air oper ated means for actuating the valve, two solenoids for controlling the passage of compressed air to the valve actuating means, said solenoids being located in normally open circuits, a permanent pole armature carried by the train to pass in close proximity to the track magnet, said armature being moved 'in one of two directions according to the polarity of the track magnet to thereby close one or the other of the circuits in which the solenoids are located.

10. An automatic train control mechanism having, in combination, a two pole track magnet connected with a block signal system, an emergency condition of the block causing current to flow through the track magnet in one direction and a caution condition of the block causing current to flow through the track magnet in the opposite direction, a valve adapted to be actuated to I one of'two directions according to the polarity of the track magnet, said armature serving to control by its position the operation of the valve actuating means.

11. An automatic train control mecha' nism having, in combination, a two pole track magnet connected with a block signal system, the current flowing through the track magnet in one of two directions according as an emergency or a caution condition prevails in the block, a valve adapted to be actuated to connect the train brake pipe with an emergency or with a service vent according to the polarity of the track magnet, means tending to hold the valve in normal position, means for actuating the valve to connect the brake pipe with either the emergency vent or the service vent, a permanent pole armature carried by the train to pass in close proximity to the track magnet to be moved thereby in one of two directions according to the polarity ofthe magnet and connections between the valve actuating means and the armature.

, 12. An automatic train control mechanism having, in combination, 'a two pole track magnet connected with a block signal system so that an emergency condition causes the current to flow through the battery in one direction anda caution condition causes the current to flow through the magnet in the opposite direction, a valve adapted to be actuated to connect the train brake pipe with an emergency tent or with a service vent according to the-polarity of the track magnet, means for actuatingthevalve, a pair of solenoids for controlling the operation of the valve actuating means, normally open circuits in which the solenoids are located, a permanent pole armature carried by the train to pass in close proximity to the track magnet and adapted to be moved in one of two directions according to the polarity of the track magnet, said armature serving to close either of the two circuits according to the direction in which it is moved and a stick magnet energized by the closing of the circuit to hold the armature in its moved position.

13. An automatic train control mechanism having, in combination, a track magnet connection with a block signal system, the polarity of the magnet varying according as emer encyor caution conditions exist in the bloc lr, a permanent pole armature carried by the tram to pass in close proxim- 14. An automatic train control mechanism 1 having, in combination, a track magnet connected with a block signal system, the polarity of the track magnet varying according as an emergency or a caution condition exists in the block, a valve casing connected with the train brake pipe and having .an emergency vent and a service vent, a valve for connecting the brake pipe with the emergency vent and with the service vent, two solenoids, normally open circuits in which the solenoids are located and means actuated when either circuit is closed for movin the valve to connect the brake pipe with either the emergency vent or the service vent, an armature carried by the train to pass in close proximity to the track magnet to be actuated thereby to close one or the other of the circuits, and a stick magnet energized by the closing of the circuit for holding the armature in'its moved position to keep the circuit closed until it is manuall broken.

15. An automatic train contro mechanism having, in combination, a track magnet connected with a block signal system and adapted to be energized when an emergency or 'a caution condition exists in the block, a valve casing connected with the train brake pi e and having a vent, a valve for sealing t e brake pipe from the vent and adapted to be actuated to connect the brake pipe with the vent when-the track magnet is energized, a piston connected with the valve, a solenoid for controlling the passage of compressed air to the piston, a normally open circuit in which the solenoid is located, and an armature carried by the train to pass in close proximity to the track magnet to be actu-- ated thereby to.close the circuit.

16. An automatic train control mechanism having, incombination, a track magnet connected with a block signal system and arranged to have a different polarity according as emergency or caution conditionsexist in the block, a-valve casing connected with the train brake pipe and having an emergency vent and a service vent, a valve for normally ,sealing the brake pipe from the vents, balanced springs for holding the valve in normal position, two pistons connected with the valve, two solenoids for controlling the passage of compressed air to the pistons, normally'open circuits in which the solenoids'are located, and an armature carried by the train to pass in close proximity to the track magnet to be actuated thereby in one of two directions according to the polarity of the magnet to close either circuit.

17. An automatic train control mechanism having, in combination, a track magnet connected with the block signal system and adapted to be energized when emergency and caution conditions exist in the block, a valve ada ted to be actuated to connect the train bra epipe with an emergency vent or with a service vent, means for actuating the valve, an armature carried by the train to pass in close proximity to the track magnet to be actuated thereby, a solenoid for controlling the operation of the valve actuating means, a normally open circuit in' which the solenoid is located, an'armature serving to close the circuit, and astick magnet energized when the circuit is closed for holding the armature in movedposition to keep the circuit closed until it is manually. broken.

18. An automatic train control mechanism having, in combination, a track magnet connected with a block signal system and arranged to have a different polarity according as an emergency or a caution condition exists in the block, a valve casing connected with the train brake pipe and having an emergency vent and a service vent, a valve for normally sealing the brake pipe from the vents, means for actuating the valve to connect the brake pipe with the emergency vent when an emergency condition exists on the track and for actuating the valve to connect the brake pipe with the service vent when a caution condition exists on the track, and means carried by the train and adapted to be actuated by the track magnet for controlling the operation of the valve actuating means.

19. An automatic train control mechanism having, in combination, a track ma et connected with a block signal system, t e polarity of the magnet varylng according as emergency or caution conditions exist in the block, a valve adapted to be actuated to connect the train brake pipe with an emergency vent or with a service vent according to the polarity of the track magnet, means for actuating the valve, two solenoid-actuated means for controlling the operation of the valve actuating means, two normally open circuits in which the solenolds are located, a permanent pole armature carried by the train to pass in close proximity to the track magnet to be moved thereby in one of two directions to close either circuit, and a pair of stick magnets located in the circuits, the stick magnet energized by the closing of the circuit serving to hold the armature in moved position to keep the circuit closed;

20. An automatic train control mechanism having, in combination, a two pole track magnet located in the road bed of the railway and connected with a block signal system, an emergency condition of the block causing the current to pass through the magnet in one direction and a caution condition causing the current to pass through the magnet in the opposite direction, a valve casing connected with the brakepipe and having an emergency vent and a service vent, a valve for normally sealing the brake pipe from the vents, two balanced springs for holding the valve in normal position, two pistons connected with the valve, two sole-- noid-actuated means for controlling the passage of compressed air to the pistons to actuate the valve, two normally open circuits in which the solenoids are located, a

of the track magnet, said arms having a permanent pole, the energization of the magnet causing the armature to be mowed in one of two directions according to its polarity to close either circuit, and a pair of stick magnets, the stick magnet energized by the closing of the circuit serving to hold the armature in moved position to keep the circuit closed until it is manually broken.

21. An automatic train control mechanism having, in combination, a valve adapted to be actuated to connect the train brake pipe with an emergency vent and with a service vent, means for actuating the valve, an armature carried by the train for controlling the valve actuating means, means located in the road bed'of the railway adapted to control the'actuation of the armature, and connections between the armature controlling means and the block signal system whereby the armature is caused to move in one direction for an emergency condition of the track and to move in the opposite direction for a caution condition of the track.

22. An automatic train control mechanism having, in combination, a valve adapted to be actuated to connect the train brake pipe with an emergency vent when an emergency condition exists on the track and with a service vent when a caution condition exists on the track, two solenoids for controlling the operation of the valve, said solenoids being located in normally open circuits, means carried by the train for closing either circuit according to track conditions, and means located in the road bed for controlling the circuit closing means connected with the block signal system to effect the closing of one circuit when an emergency condition exists on the track and to effect the closing of the other circuit when a caution condition exists on the track.

23. An automatic train control mechanism having, in combination, a valve adapted to be moved in one direction to connect the train brake pipe with an emergency vent and in the opposite direction to connect the train brake pipe with a service vent, means for actuating the valve, two solenoids for controlling the operation of the valve actuating means, each solenoid being located in a normally open circuit, circuit closing means carried by the train for closing either circuit according as emergency or caution conditions exist on the track, and means located'in the road bed of the railway connected with theblock signal system for controlling the operation of the circuit closing means according as the block signal system indicates an emergency or'a caution condition of the track.

' JOHN L. HAYTER.

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